Post Harvest Technology of Mushroom

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POST HARVEST TECHNOLOGY OF MUSHROOMS Technical Bulletin R.D. Rai T. Arumuganathan National Research Centre for Mushroom (Indian Council of Agricultural Research) Chambaghat, Solan-173 213 (HP)

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Technical Bulletin

R.D. Rai

T. Arumuganathan

National Research Centre for Mushroom(Indian Council of Agricultural Research)

Chambaghat, Solan-173 213 (HP)

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Printed : 2008, 1000 Copies

Published by :DirectorNational Research Centre for Mushroom (ICAR)Chambaghat, Solan – 173 213 (HP), INDIAPhone: 01792-230451; Fax: 01792-231207E-mail: [email protected]:

N.R.C.M. 2008All rights reserved. No part of this technical bulletin may be reproduced inany form or by any means without prior permission in writing from thecompetent authority.

Designed & Printed at:Yugantar Prakashan Pvt. Ltd.WH-23, Mayapuri Indl. Area, New Delhi-64Ph.: 011-28115949, 28116018


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1 Introduction 1

2 Postharvest physiological and biochemical changes 7

3 Storage of fresh mushrooms 12

4 Packaging 16

5 Long-term storage 29

6 Value-added products 48

7 Canning unit 59

8 Economics of canning 66

9 Economics of pickling 68

10 Sources of machinery / equipments 70

11 References 72

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The man has been consuming mushrooms as food, medicine and even asintoxicant, since time immemorial by collecting them from the wild.Mushroom-hunting is still a game or a hobby with many. The appearance ofmushrooms in the wild is, however, uncertain and seasonal depending uponmany factors like habitat and climate etc. The need and greed to ensure theregular availability of mushrooms impelled the mankind to domesticate someof the most delicious mushrooms. It started with the domestication of paddystraw mushroom (Volvariella volvaceae) and black ear mushroom (Auriculariapolytrica) in China, but undoubtedly it was the introduction and cultivation ofthe common white button mushroom (Agaricus bisporus) in the limestonecaves in France in late eighteenth century which can be truly termed as biggestmilestone in the history of mushroom production. Since then more than 20types of edible and medicinal mushrooms have been domesticated andtechnologies have been improved to the commercial level.

Realizing the importance of mushrooms for ensuring nutritional and socialsecurity of the underprivileged small farmers and landless labourers, the IndianCouncil of Agricultural Research established the National Research Centrefor Mushroom (NRCM) in 1983 to conduct research and transfer the technologyon all aspects of mushrooms. There are very few countries like India, whichcan boast of a multidisciplinary national research establishment exclusivelyon mushrooms. During the past 25 years, the NRCM has delivered the resultsand met the objectives for which it was established; there has been many foldsincrease in the productivity and production of the common button mushroom.Besides, the mushroom growing has spread far and wide in various regions ofthe country. Introduction and cultivation of the tropical mushrooms like oyster,paddy straw and milky mushrooms have brought in much-neededdiversification in the mushroom portfolio of the country. Like any other foodcrop research organization, NRCM too has crop improvement (breeding), cropproduction (agronomy), crop protection and crop nutrition & utilization(postharvest technology) programmes and accordingly the sections (divisions).Keeping in view very short shelf -life of mushrooms, postharvest research wasgiven due emphasis right from the establishment of the NRCM. The centrehas well-equipped postharvest laboratory with canning unit, cabinet drier,dehumidified air cabinet drier, freeze drier, fluidized bed drier, water activity


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meter, modified atmosphere packaging machine and O2 & CO2 analyser etc.Besides the techniques for proper packaging and storage, many processingand value-addition technologies of mushrooms have been developed at thecentre. A need was felt to bring out a comprehensive technical bulletin onthese technologies to serve the needs of the researcher, grower, processor andconsumer.

I must congratulate the authors, Dr. R.D.Rai and Er. T. Arumuganathanfor bringing out the bulletin in a unique blend of scientific as well as popularformat. I am happy to present the bulletin to the mushroom fraternity.

Rajendra Prasad TewariDirectorNational Research Centre forMushroom, Solan – 173 213 (HP)


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Production and consumption of mushrooms have tremendously increasedin India due mainly to increased awareness of the commercial and nutritionalsignificance of this commodity. Needless to emphasize the relationship betweenthe consumption of such fancied items and the purchasing power of the masses;consumption of mushrooms shall continue to rise with the currentphenomenon of rise in the income level of the populace.

Mushrooms have very short shelflife – these cannot be stored or transportedfor more than 24 hours at the ambient conditions prevailing in most parts ofyear and the country. Browning, veil-opening, weight-loss and microbialspoilage are the most common postharvest changes in the mushrooms whichoften result into enormous economic losses. Proper, sound and appropriatepostharvest practices of storage and processing are needed to sustain thebudding mushroom farming and industry in the country. In India, more than90% of the total mushroom production is still contributed by the commonbutton mushroom (Agaricus bisporus). Understandably and justifiably, mostof the postharvest aspects dealt in the present publication relate to thismushroom. However, many of these hold true for other mushrooms as welland the technologies can be easily extended, with slight modifications, to othermushrooms.

We have endeavoured to deal with most important postharvest aspects ofmushrooms – physiological and biochemical changes, packaging and storageof fresh mushrooms, long-term storage, processing and value-addition. As thecanning and pickling are the most important preservation technologies in thecountry, for the domestic as well as international trade, these aspects havebeen covered in detail, including the infrastructure, technical details and alsothe economics of these processes. Efforts have also been made to enlist theleading manufacturers and suppliers of the machinery and equipments.

While drafting the bulletin, we have kept in mind the needs of both,researchers as well as growers. The citations have been incorporated for themost important post harvest aspects and about 185 references are given at theend of the bulletin for the researchers and students concerned with thepostharvest R & D on mushrooms. The growers and industrialists shall find

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the style quite understandable; they have to just ignore the citations andreferences. We have tried to present this technical bulletin in a blend of technical& popular format.

Many of the technologies have been developed, refined, modified andimproved at the NRCM, as would be evident from the photographs. We would,therefore, like to acknowledge the contributions of our predecessors andcolleagues who, at any stage and in any form, have been associated with thedevelopment of the technologies – Dr. Sanjeev Saxena, Dr. V. Chandrasekar, Dr.O.P. Ahlawat, Ms. Kusum Ahlawat, Mr. Anil Hemkar, Dr. Shwet Kamal, Er.Rajesh Kumar, Mr. Vinay Kumar Khare, Mr. Lekh Raj Rana and Mr. Raj Kumar.We wish to thank Ms. Shailja Verma and Ms. Sunila Thakur for excellentsupport in the photography and word processing, respectively.



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The production and consumptionof mushrooms is increasing very fastthroughout the world, mainly due togreater and greater awareness of theirnutritive and medicinal attributes,besides, of course, unique flavour andtexture; consumption of such fancieditems is also a natural corollary to thegeneral economic development of acountry and, needless to say, the worldeconomies are booming. Worldproduction of mushrooms is estimatedabout 12 million tonnes and theannual growth rate is still above 8 %;India too, though late starter, is fastcatching up and the currentproduction has crossed lakh tonnemark with annual growth rate of above15 %; the venture is no more confinedto the seasonal growing in thenorthern region, it has spread far andwide in the country. Besides theseasonal farmers, many bigenvironmentally-controlled unitshave also come up as export-orientedunits. The country is proud to havethe biggest mushroom unit of theworld producing 200 tonnes buttonmushroom per day and its exportaccounts for about 25 % of the USimports.

Currently, about twenty species ofmushrooms are being commerciallycultivated world over, but significant


production is of the button mushroom(Agaricus bisporus) (Fig. 1), Shiitake(Lentinula edodes) (Fig. 2), Oystermushroom (Pleurotus spp.) (Fig. 3),Black ear mushroom (Auriculariapolytricha) and paddy strawmushroom (Volvariella volvacea) (Fig.4). In India, button mushroom stillcontributes more than 85 % of the totalmushroom production, though its

Fig. 1. Button mushroom(Agaricus bisporus)

Fig. 2. Shiitake mushroom(Lentinula edodes)


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Fig. 3. Oyster mushroom(Pleurotus florida)

share is below 40 % in the global trade.Besides the button mushroom, oystermushroom and paddy strawmushroom are the other types grownin limited but significant quantitiesmostly in the tropical pockets of thecountry. Milky mushroom (Calocybeindica) (Fig. 5), which may be the onlycommercial mushroom with fruiting

temperature between 35-400C, is thenew introduction from India to theworld and its production is catchingup fast in different parts of thecountry during the summer monthsand the mushroom has revolutionizedthe so-called off-season mushroomgrowing. Fresh mushroom market islargely catered by the seasonalgrowers who do not have cool- chainstorage and transport facilities andsell the produce in highly localisedmarkets; needless to mention thatsuch seasonal players at times face theconsequences of over-saturatedmarket and understandably resort todistress sales at un-remunerativeprices.

Mushrooms are a good source ofvery good quality protein especiallyrich in lysine and thus supplementwell the cereal based Indian diet. FAOrecognizes mushrooms as the rightsource of protein to fight protein

Fig. 4. Paddy straw mushroom(Volvariella volvacea)

Fig. 5. Milky mushroom(Calocybe indica)

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malnutrition in the cereal–dependentdeveloping countries like India. Theseare very low-calorie food suited to allthose interested in cutting down thecalorie intake, like obese persons.Being low in fat, but desirable fat

devoid of cholesterol, these make anideal diet for the heart patients.Mushrooms are a low-calorie: highprotein diet, with no starch andsugars, and are called the diabeticsdelight (Tables 1 and 2). These are also

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Table 1. Nutritional properties (g/100g dw) of culinary mushrooms

Mushroom Protein Fat Poly Total Saturated Carbohydrate Complexunsaturated unsaturated fat carbohydrate

fat fat

A.bisporus 34.44 3.10 1.43 1.46 0.30 47.38 24.68Portobello

A.bisporus 33.48 2.39 0.41 0.44 0.26 46.17 24.27Crimni

Lentinus 32.93 3.73 1.30 1.36 0.22 47.60 31.80edodesShiitake

Pleurotus 27.25 2.75 1.16 1.32 0.20 56.61 35.31ostreatusPearl oyster

Pleurotus 19.23 2.70 0.53 0.62 0.11 63.40 51.60pulmonarius(sajor caju)Phoenix oyster

Source: Stamets (2005)

Table 2. Nutritional properties of culinary mushrooms

Mushroom Sugar Calories Calcium Copper Iron Potassium Sodium Selenium(g/100g) (mg /100g) (mg /100g) (mg /100g) (mg /100g) (mg /100g) (mg /100g)

A.bisporus 22.70 355 23 4.33 2.1 4500 52 0.415Portobello

A.bisporus 21.90 340 9 20.80 4.8 4800 3 0.066CrimniLentinus edodes15.80 356 23 1.23 5.5 2700 18 0.076Shiitake

Pleurotus 22.30 360 20 1.69 9.1 2700 48 0.035ostreatusPearl oyster

Pleurotus 11.80 355 9 1.03 6.5 2600 16 0.09pulmonarius(sajor caju)Phoenix oyster

Source: Stamets (2005)

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rich in vitamins and mineralsespecially B- Complex and iron.Vitamin B-12 and Folic acid, whichare normally not found in vegetarianitems are present in mushrooms andalong with availability of iron andprotein, are reported to maintainhemoglobin level as single source of

diet; anemia is rampant in Indiaspecially in pregnant women (Tables3 and 4). With very high fibre andalkaline elements, mushrooms aresuited to those suffering fromhyperacidity and constipation;consumption of fibre has gainedimportance in general health

R.D. Rai & T. Arumuganathan


Table 3. Nutritional properties of culinary-medicinal mushrooms

Mushroom Dietary Thiamine B1 Riboflavin B2 Niacin B3 Pantothenic Vitamin CVitamin DFiber (mg /100g) (mg /100g) (mg /100g) acid B5 (mg /100g) (lU/100g)

(g/100g) (mg /100g)

A.bisporus 20.90 0.27 4.13 69.20 12.70 0 235Portobello

A.bisporus 19.90 0.23 3.49 38.50 21.70 0 26Crimni

Lentinus edodes28.80 0.25 2.30 20.40 11.60 0 110Shiitake

Pleurotus 34.10 0.16 2.40 54.30 12.30 0 116ostreatusPearl oyster

Pleurotus 48.60 0.10 1.68 23.80 8.80 0 178pulmonarius(sajor caju)Phoenix oyster

Source: Stamets (2005)

Table 4. Comparison of mushroom with common vegetables per 100 g of article

Name Calories Moisture Fat Carbohydrate(%) Protein(dry weight basis)

Mushroom 16 91.1 0.3 4.4 26.9

Beet root 42 87.6 0.1 9.6 12.9

Brinjal 24 92.7 0.2 5.5 15.1

Cabbage 24 92.4 0.2 5.3 18.4

Cauliflower 25 91.7 0.2 4.9 28.8

Celery 18 93.7 0.2 3.7 20.6

Green beans 35 88.9 0.2 7.7 21.6

Green peas 98 74.3 0.4 17.7 26.1

Lima beans 128 66.5 0.8 23.5 22.2

Potato 83 73.8 0.1 19.1 7.6

Source: Rai (1995)

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maintenance. Many mushroomspossess significant medicinalattributes like hypocholesterolemic,hypoglycemic and hypotensiveproperties. Mushrooms also exhibitstrong anti-oxidant andhepatoprotective properties.

Post harvest losses are very highin most of the horticulturalcommodities and it may be one of thehighest in mushrooms. Mushroomseven after harvesting continue to grow,respire, mature and senesce resultingin weight loss, veil-opening, browning,wilting and finally in spoilage. Almostall the mushrooms have very shortshelf-life but the paddy strawmushroom has the shortest (few hoursat the ambient) and Milky has verygood shelf-life (3-5 days) if microbialspoilage is taken care of. Mostdamaging post harvest changes inmushrooms vary with species—it isblackening in the button mushroom,cap-opening in the paddy strawmushroom and mucilage in the oystermushroom, which affect theirmarketability significantly. Weightloss is very serious problem in all themushrooms as these contain very highmoisture (85-90 %) and are notprotected by the conventional cuticle.Due to very high moisture and richnutritive value, microbial spoilage inmushrooms is also a problem. In caseof the button mushroom all the fourmost deleterious changes namely,browning, veil-opening, weight lossand microbial spoilage ask for the

utmost post-harvest care. Needless tosay that these changes are alsoaccompanied by changes in thenutritional and medicinal attributesof these mushrooms.

Utmost post harvest care ofmushrooms is needed not only for thefresh market but also for theprocessing, as most of these changesare irreversible. Gluts and distresssales are not uncommon in mushroommarketing specially during the peakmonths when seasonal produce hitsthe market in a big way. Withholdingof the fresh mushrooms at any pointof the chain— grower, wholesaler orthe retailer—, is neither feasible noradvisable as it may result in furtherdeterioration in quality leading to thetotal loss. Information about properpost harvest care and processing ofsuch a perishable commodity istherefore of vital importance to keepthe wheels of this industry moving atthe right speed; with the adoption ofproper packaging, storage andprocessing technologies, problems inmarketing, like seasonal gluts anddistress sales, can also be ameliorated.

A sizeable production of the buttonmushroom and almost entireproduction of other mushrooms stillcomes from the small seasonalgrowers although many commercialunits produce button mushroomthroughout the year under thecontrolled conditions. The problem ofgluts exacerbates during the so-called

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peak season (December-February).India is predominantly a market forthe fresh mushrooms, with very littlequantity sold as canned mainly for theinstitutional consumers. Almostentire export is in the canned formaccompanied with mushroom picklesas a bye-product of the canneries. Butfuture is going to witness greatercontribution from the processingsector, both as stored and reallyprocessed mushrooms. Improved postharvest practices for the storage andprocessing of mushrooms includingvalue-addition, readymade or ready-to-make products will not only bedemanded but will add to the returnsto the growers as well as processors.

Two most common post harvestpractices and aspects of mushroomsare: proper packaging and storage forthe fresh mushrooms; and processingfor long-term storage as well as value-addition. Market for the freshcommodities is likely to continue;reverse trend has already started inthe countries where processedproducts were being consumed.Therefore most important of all, it isthe proper packaging and storage of

the fresh mushrooms which shouldreceive the attention of all the playersin the field—researchers, growers andtraders. Besides canning, drying,steeping and pickling currentlyresorted to for the long-term storageand trade, it is the production andconsumption of the readymade orready-to-make value-added mushroomproducts which have, of late, beenreceiving the attention of themushroom research and industry.Mushroom-based soup powder,noodles and biscuits are already onthe shelves. Technologies for ready-to-make mushroom pizza, mushroomcurry in retortable pouches, nuggets,ketchup, preserve in sugar syrup(murabba) have been developed. Thebulletin aims at giving current statusof the science, art and technology forthe post harvest storage, processingand value-addition of mushrooms withspecial emphasis on the buttonmushroom keeping in view its presentproduction and consumption in thecountry. Adoption of proper postharvest practices of the storage andprocessing may partially amelioratethe problems of marketing ofmushrooms during the peak periods.

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Mushrooms, like other fruits andvegetables, respire, grow, mature andsenesce after the harvest which affectquality and shelf-life significantly.Understanding of the postharvestphysiological processes which affectthe quality and shelf life and how thesecould be managed to ameliorate thesituation is required.

2.1. Colour

Whiteness is the most importantquality attribute in the buttonmushroom, besides, of course, shapeand size. In a survey conducted in UKon the preference of the consumersabout quality in the buttonmushroom, whiteness got the greatestscore. Whiteness categories formushrooms have been quantified byGormley (1975) based on Hunter L*(Lightness values); (1) Higher than 93,excellent (100 is the theoreticalmaximum); (2) 90-93, very good; (3) 86-89, good; (4) 80-85, reasonable; (5) 69-79, poor; (6) below 69, very poor.Mushrooms with values below 80 wereconsidered unacceptable at wholesaleand below 69 at retail. Lower storagetemperature retarded the changes.‘Smooth white’ is term used by thespawn producers to denote the strains

which will give smooth (not scaly)white fruit bodies. Hyphae of whitestrains are virtually colourless andtranslucent but they contain enzymeswhich under certain conditions reactwith the substrates in the cell contentto form pigmented compounds, thereason for postharvest mushroombrowning (Burton, 1986). Tyrosinase,commonly known as phenol oxidase(monophenol monooxygenase EC1.14.18.1) is responsible for postharvest browning (Fig. 6).Mishandling during harvesting,enzymes and substrates, which areperhaps in separate cellcompartments, get mixed up and thereaction is activated. Colourlessphenols, after initial reaction formquinones, which transform and

Fig. 6. Enzymatic browning in buttonmushroom


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polymerise into pink, purple to browncompounds. Like any enzymaticreaction, the rate of reaction willdepend upon quantity and activity ofenzyme protein, amount of substrateavailable and favourable conditionsfor the reaction (pH, temperature etc).But no doubt, brown mushroomsrepresent mishandled and agedmushrooms after the harvest(Nichols, 1985).

Susceptibility of white buttonmushroom to browning is a seriouscommercial problem. It would beimportant and beneficial tounderstand the enzyme and itsmechanism of action. Tyrosinase is acopper containing enzyme found inAgaricus bisporus fruit bodies andcatalyses hydroxylation ofmonophenols to diphenols whichalongwith the native diphenols arethen oxidised to quinones whichpolymerise to form brown insolublepigment called melanin. Tyrosinase isnormally found as 4 isozymes (Robband Gutteridge, 1981) with differentsubstrate affinities but similar aminoacid composition. The enzyme iscomposed of two different types ofsubunits: a light chain of MW 13600and a heavy chain of MW 43700. It hasbeen thought that the predominantform of enzyme is a tetramer of twoheavy and tow light chains. Somepeptide inhibitors of Tyrosinase havebeen reported in Agaricus bisporus(Hammond and Wood, 1985).

Tyrosine and DOPA havetraditionally been considered as invivo substrate for the Tyrosinase. Ithas been suggested that L-glutaminyl-4-hydroxy benzene (GHB) is thenatural substrate for mushroomtyrosinase (Stussi and Rast, 1981).GHB is present in larger amountsthan DOPA in mushroom and insimilar amounts to tyrosine.

Oxidation of phenol by polyphenoloxidase resulted in the browningcomplex (Yamaguchi et al., 1970;Nichols, 1985; Rai and Saxena, 1988;Bartley et al., 1991). Fang et al. (1971)were able to inhibit polyphenoloxidase activity in sliced mushroomby dipping in a solution of sodiummetabisulphite (200 ppm SO2) and 2per cent NaCl and blanching in boilingwater for 2 min followed byevaporative cooling. Increasedbrowning of mushrooms stored at hightemperature was observed and wascorrelated with increased activity ofpolyphenol oxidase (Murr and Morris,1974; Goodenough, 1976; Goodenoughand Ricketts, 1977).

The enzyme tyrosinase catalysesthe reaction of phenols with oxygenfrom the air. Button mushroom ishighly prone to enzymatic browningwhen the surface of the mushroom isexposed to air. Enzymes viz.,tyrosinase and poly phenol oxidasereleased at the surface act on thepolyphenols present in the mushroom

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and oxidize them to orthoquinones(Murr and Morris, 1975b;Swaminathan, 1988; Jolivet et al.,1995). The essential components of thebrowning reaction viz., phenols andtyrosinase are kept in separate sub-cellular compartments of the hyphae.The phenols are probably confined tothe vacuole and the tyrosinase to thecytoplasm as in higher plants (Mayerand Harel, 1979). During handling,storage and ageing of mushrooms, themembranes separating thecompartments are ruptured andbreakdown the contents mix, theenzyme becomes activated and thebrowning reaction begins (Burton,1986; Burton et al., 1995; Jolivet et al.,1995). Tyrosinase is thereforecommercially important in thestorage of mushrooms because itcatalyzes the first step in theformation of melanins (Long andAlben, 1968; Smith et al., 1993;Wichers et al., 1995). Tyrosinase canoxide both ortho (o)- and para (p)-diphenols and are usually inactiveagainst monophenols (Wichers et al.,1995; Jolivet et al., 1995).

Non-enzymatic browning is duemainly to (i) Maillard reactioninvolving interaction betweenreducing sugars, amino acids andproteins (ii) reaction of oxidationproducts of ascorbic acid with proteinsor amino acids (iii) reaction ofoxidation products of polyunsaturatedfatty acids with amino acids andproteins and (iv) caramelisation of

sugars. Mushrooms do containsugars, amino acids and proteins andhence non-enzymatic browning isinevitable when this high moisturecontent product is stored above 5°C(Swaminathan, 1988).

2.2. Post harvest metabolism

Harvesting results in severing thesupply of substrates by the myceliumfor growth and respiration despite thefact that mushrooms after harvestcontinue to grow (expand) withdevelopment of gills and formation ofbasidiospores. Expectedly, metabolicshift takes place resulting incompositional changes. The shortershelf life of mushrooms is due to itsvery high respiration rate-of about28.2-43.6 mg CO2 per kg fresh weightper hour at 0°C (Hammond andNichols, 1975; USDA, 1977) and 280mg CO2 per kg fresh weight per hourat 19°C (Nichols, 1985). Therespiratory heat in mushrooms isreported to be 14 kcal / kg / 24 h at20°C (Nichols and Hammond, 1975)and mannitol acts as the preferredpost harvest respiratory substrate.There is deceleration in participationof HMP pathway with reduced G-6-PDH activity (Hammond, 1979). Itmay be mentioned that reverse was thecase during crop appearance- themetabolic tilt was towards activatedHMP shunt with enhanced G-6-PDHsynthesizing NADPH favouringmannitol synthesis.

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There is decrease in glycogen andtrehalose contents during post harveststorage indicating their role assecondary respiratory substrates aftermannitol. Storage of mushrooms athigher temperature (18 to 20°C)resulted in reduction in protein withaccumulation of free amino acids dueto activated protease enzyme activity(Murr and Morris, 1975b; Rai andSaxena, 1988) and decrease in freeamino acids and cell wall glucan(Murr and Morris, 1975a; Hammond,1979). Lower storage temperatureretarded the changes. At highertemperature urea accumulation(Hammond, 1979) and breakdown ofnucleic acids and other nitrogenoussubstances may occur. Chitinproduction is essential for growth ofthe stipe and for cap expansion, whichoccur after harvest. Thesedevelopmental changes could beprevented by application of the chitinsynthetase inhibitor polyoxin D (Woodand Hammond, 1977).

Button mushroom stored at 10 and200C shows a sigmoid pattern ofgrowth, but at 00C growth is retardedsubstantially. The post-harvestgrowth exhibited at 10 and 200C couldbe related to a decrease in free aminonitrogen while at 00C the level of freeamino nitrogen significantly increasesduring storage. Protease activity inthe tissue increases from 0, 10 and200C. It appears that the postharvestmaturation of mushrooms is promotedby the utilization of low molecular

weight nitrogenous compounds formedthrough increased proteindegradation. Mushrooms stored at200C toughen and mature faster thanat 0 and 100C (Pathak et al., 1998).

Eby et al. (1977) reported a changein electrophoretic protein patternsduring storage at 12°C, and anincrease in free amino acids.Reduction in temperature to 0°Cprevented the increase in proteaseactivity, but caused a greateraccumulation of free amino acids(Murr and Morris, 1975a). Cytokininshave been reported to affect variousgrowth processes in button mushroom(Hammond and Wood, 1985; Braaksmaet al., 2001). Zeatin and Zeatinribonucleotide were found insporophores and stimulated capopening at low levels (Dua andJandaik, 1979; Kovacs, 1982 a).Kovacs (1982b) also reported thatpostharvest treatment of mushroomswith kinetin (100 mg / kg) inhibitedcap opening during subsequentstorage, while the low concentration(16 to 32 mg / kg) stimulated it.Hammond and Nichols (1975) foundthat mannitol was the majorcarbohydrate (13 per cent dry weight)and the main respiratory substrateduring storage of button mushroom.They also reported that the rate of lossof mannitol was sufficient to accountfor about half of the carbon respired.Maximum ethylene productionoccurred subsequent to veil-break asthe gill colour changed from pink to

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brown followed by a decline as thefruit body sporulated and senesced(Wood et al., 1977).

Hammond (1979) reported adecrease in non-structuralpolysaccharides from 10 to 5 per centafter 4 days of storage and an increaseof 50 per cent in chitin content of cellwalls. The total sugars, solubleproteins and total phenol content ofwhite button mushroom duringstorage declined while, there was anupsurge in the polyphenol oxidaseenzyme activity (Rai and Saxena,1989). De la Plaza et al. (1995) reportedthat the atmosphere in PE packages(10 per cent O2 + 7 per cent CO2)delayed firmness-loss but induced themetabolic changes (sugar and organicacids) and colour (yellowness) andreduced the mushroom quality at 18°Cafter 8 days of storage at 3°C.Kompany and Rene (1995) used three(100, 25 and 8 min) freezing rates (timerequired to reduce temperature ofmushroom centre from initial 20°C to-20°C) and found that flavourretention was best at the highestfreezing rate (8 min). During frozenstorage, maximum loss in flavour wasreported within first 5 days after which

no significant loss was found. Theyfound that there was no significantdifference in flavour of frozenmushroom during storage at –20°C or–60°C.

Mushrooms with high dry mattercontent had an increased firmness,better shelf life and decreasedshrinking during canning (Van Loonet al., 2000). Ates et al. (2001) usedhoney to inhibit the PolyphenolOxidase (PPO) activity in mushroomand observed that the lowestArrhenius activation energy (Ea) was27.71 kJ/mol, whereas Ea in the controlwas 83.14 kJ/mol. This implies thatthe temperature coefficient of PPOinactivation was lower in the presenceof honey. Quality indices of storedmushrooms were determined afterexposure to ethyl alcohol and methyljasmonate with ethyl alcohol vapours.Ethyl alcohol vapour markedlyinhibited cap expansion, stipeelongation and maturity comparedwith the control. Methyl jasmonatewith ethanol vapours was shown to havebeneficial effect on whiteness,appearance and decreased activity ofactive form of catechol oxidase (Czapski,2001).

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Obviously, fresh mushrooms needto be properly stored to retard postharvest deterioration till these areconsumed. Needless to reiterate thatthe refrigeration or cold-storage is themost essential part of the post harvestcare of all the horticulturalcommodities including mushrooms.Pretreatments, if any, packing andprecooling precede the refrigeratedstorage in most cases.

3.1. Cooling and refrigeration

Cold-preservation of mushroomsis the most important aspect of thestorage and can be classified in twocategories: refrigeration and freezing.Household and commercialrefrigerators usually run at 4–70C.Cold or chill storage may use a slightlylower temperature (–1 to –40C),depending upon the freshness of themushrooms to be refrigerated.Freezing is done at a temperature ofbelow -180C. Chill storage willpreserve perishables for days or weeksand frozen storage (deep freezing) willpreserve for months or even years.Refrigeration has certain advantagesover freezing as it takes less energyto cool mushrooms to just above itsfreezing point than to freeze it. Thetemperature of the button mushroom

after picking, which varies between 15and 180C, rises steadily during thestorage due to respiration andatmospheric temperature and the heatcauses deterioration in quality; inaddition, the respiratory rateincreases with the increase in thestorage temperature leading to avicious cycle. It has been estimatedthat mushrooms at 100C have 3.5times higher respiratory activity thanthose at 00C, which necessitatesimmediate shifting of mushrooms tothe refrigerated zone. Hence the heatshould be removed immediately afterthe harvest and the temperature ofmushrooms should be brought downto 4-50C as quickly as possible. Lowtemperature retards the growth ofmicroorganisms, reduces the rate ofpostharvest metabolic activities of themushroom tissues and minimizes themoisture loss. The choice of thecooling system depends upon thequantity to be handled; it may be arefrigerator for a small grower orconsumer a cold room with all thefacilities for a commercial grower.Forced-chilled air, ice-bank or vacuum-cooling systems are the other systemsin vogue at commercial level. The viewof button mushrooms during therefrigerated transport and storage isshown in Figure 7.


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button mushrooms were slowed downat 00C ensuring the maintenance ofexcellent quality (Murr and Morris,1975 a). Minamide et al. (1980)observed that the shelf-life of thebutton mushroom was about 14-20days at 10C, about 10 days at 60C and 2to 3 days at 200C. Also, polyphenoloxidase activity and respiration ratewere enhanced at 200C storage. Bakeret al. (1981) observed that in buttonmushrooms, forced air coolingresulted in a weight loss of about 2.5per cent within 15-30 min. Minamideet al. (1985) reported thathydrocooling of button mushroomnear their freezing point for 3 h within6 h of harvest, packing in 100 per centnitrogen gas (N2) for 2 h and thentransferring to room temperature(200C) preserved them for 15 days.

Chopra et al. (1985) recommended100 gauge polythene bags with 0.5 percent venting area for packing buttonmushroom in case of refrigeratedstorage. Nichols (1985) recommendedoptimum temperature and relativehumidity for storage of buttonmushrooms as 0-20C and 85-90 percent respectively. Saxena and Rai(1988) however, reported the adverseeffects of over-ventilation of polythenepacks; mushrooms were bestpreserved in non-perforated 100 gaugepolypropylene bags kept at 50C.Varszegi (2003) conducted anexperiment to determine therelationship between the bacterialgrowth on mushroom cap and the pre-

Fig. 7. Button mushroom packs andstacks during refrigerated transport

and storage

The size and shape of the packsplay important role in the selection ofthe cooling room system and design.Packs with more than 10 kgmushrooms or with 15 cm thick layersof mushroom cause problems. Verticalflow of air is more suitable for cooling.The mushrooms should not be storedin the same cooler alongwith fruits asthe gases produced by fruits causediscolouration of mushrooms. As thesimple forced-chill air-cooling systemis time consuming, the vacuumcooling is becoming popular. To ensurehigh quality mushrooms in themarket place with enhanced shelf-life,these must be cooled as quickly aspossible after picking and kept coolthroughout the cold chain (Rai andArumuganathan, 2003).

Storage under low temperature isan excellent method for restrictingdeterioration of harvested mushroomsfor a limited period of time. Thematuration and textural changes in

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cooling methods (forced wet coolingand vacuum cooling) and found thatvacuum cooling provided the longestperiod of time needed to reach themaximum value of microbialpopulation and this method was foundbeneficial for the quality. Blanchingfor a short period is absolutelyessential for producing good qualityfrozen mushrooms. Steam blanchingfor 3 min prior to freezing recordedretention of qualities of oystermushroom also (Das and Pathanayak,2003).

3.2. Vacuum-cooling

In vacuum-cooling, the water incell walls and interhydral spaces ofmushrooms gets evaporated under lowpressure, and the evaporative coolinglowers the temperature from theambient to 20C in 15 to 20 min.Vacuum-cooling is a uniform andfaster process, where mushrooms aresubjected to very low pressure andwater evaporates giving off the latentheat of vaporization. The vacuum-cooled mushrooms have superiorcolour than conventional-cooledmushrooms. The major drawback ofthe system is the high capital cost andloss of fresh weight of the produceduring the process of cooling. Fillingand emptying the cooling chamberadds to the marketing cost. However,air spray-moist chillers can also coolthe mushrooms rapidly. Thetemperature can be lowered by 16-180Cin an hour without any moisture loss.

3.3. Ice-bank cooling

With a view to reduce the weightloss during the conventional vacuum-cooling, ice bank cooling ofmushrooms is now in vogue where astack of mushrooms is passed throughforced draft of chilled but humidifiedair from the ice bank (Water bodymaintained at sub zero temperature).

3.4. Irradiation

Radiation preservation offers amethod of “cold sterilization” wherethe mushrooms may be preservedwithout marked change in theirnatural characters. Low dosages of γ-radiation could be used to reduce themicrobial contamination and extendthe shelf-life of mushrooms. However,irradiation should be givenimmediately after harvest foroptimum benefits. Various types ofbeneficial effects of radiation havebeen observed in preserving the buttonmushroom (Staden, 1967; Campbell etal., 1968; Wahid and Kovacs, 1980; Royand Bahl, 1984 a; Lescane, 1994) andoyster mushroom (Roy et al., 2000).Irradiation has been found to delay thematuration i.e. development of cap,stalk, gill and spore and also reducethe loss of water, colour, flavour,texture and finally the quality losses.Cobalt 60 (Co60) has been used as acommon source of γ rays. A dose of 400krad gave whiter buttons than thecontrols when the atmospherictemperature during growth and

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subsequent handling was slightlylower than 200C (Roy and Bahl, 1984b). A dose of 10 kGy (Kilo Gray) isreported to completely destroymicroorganisms. Enhancement inshelf-life of Agaricus bisporus upto aperiod of 10 days was achieved byapplication of gamma rays close to 2kGy and storage at 100C (Lescane,1994). Irradiation reduces theincidence of fungal and bacterialinfection and also retards thebreakdown of mannitol and trehalose.However, the loss of flavourcomponents has been noticed inirradiated mushrooms. But aminoacids in fresh mushrooms were betterpreserved by γ irradiation and thisshowed that irradiation at low levelsproved better than irradiation levelsof 1 & 2 kGy (Roy and Bahl, 1984 a).

Benoit et al. (2000) investigated theeffect of gamma irradiation on somebiochemical parameters of themushrooms: higher dosessignificantly reduced the rate ofrespiration compared to samples

irradiated with 0.5 kGy and non-irradiated mushrooms. Ionizingtreatments significantly increasedphenylalanine ammonia-lyase (PAL)activity and total phenolicconcentration.

Koorapati et al. (2004) evaluatedthe effect of electron-beam irradiationon quality of white button mushroomand observed that irradiation levelsabove 0.5 kGy prevented microbes-induced browning. Theyrecommended that irradiation at 1kGy was the most effective inextending the shelf-life of mushroomslices. A study was conducted byEscriche et al. (2001) to determine theeffect of ozone on post harvest qualityof mushroom. Ozone treatment (100mg / h) of mushrooms prior topackaging increased the externalbrowning and reduced the internalbrowning rates. The ozone treatmentexhibited no significant differences interms of texture, maturity index andweight loss of mushrooms.

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Packaging plays very importantrole in handling, marketing andconsumption of the produce andproducts, protects the quality duringthe storage and transport, keeping inretail and storage with the consumer.Packaging of mushrooms from theproduction site upto the consumerincluding packaging for export marketis an important aspect of post harvesthandling. Generally, the see-throughpackaging increases the consumerconfidence in the product. If thepackaging and storage is not doneproperly, mushrooms not onlydeteriorate in their saleable qualitybut also in nutritional quality due toenzymatic changes (Nichols andHammond, 1975; Rai and Saxena, 1988& 1989; Rai et al., 1988). The tray-packed button mushroom and milky

mushroom are shown in Figures 8 and9, respectively.

The oyster mushrooms areharvested, stem-cut and adhered straw,if any, is removed. The cleanedmushrooms are packed inpolypropylene bags of about 100 gaugethickness with perforations havingvent area of above 5 per cent. Thoughthe perforation causes slightreduction in weight during thestorage, it helps maintain thefreshness and firmness of the produce.Storage of dhingri at very lowtemperatures especially in non-perforated polypacks results incondensation of water, sliminess ofthe surface and softening of thetexture. Cooling with positiveventilation is desirable i.e. cold air

Fig. 8. Tray-packed button mushroom


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should be directed through the packedproduce. For transporting dhingri, thefruitbodies are stacked in trays orbaskets. Few polypouches containingcrushed ice are kept alongwithmushrooms if refrigerated transportis not available. The tray is thencovered with thin polythene sheetwith perforation (Fig. 10). Theprepacked polythene packs withperforations may also be transportedin this way.

Paddy straw mushrooms arepacked in polythene bags (Fig. 11) aswell as tray packs (Fig. 12). As verylow temperature storage causes frostinjury and deterioration in quality, thebest way of storage is at 10-150C inpolythene bags with perforations.Mushrooms packed in bamboo basketswith an aeration channel at the centerand dry ice wrapped in paper placedabove mushrooms, is in practice fortransportation in Taiwan. Packing inFig. 9. Tray-packed milky mushroom

Fig. 10. Tray-packed oyster mushroom

Fig. 11. Packed paddy straw mushroom

Fig. 12. Tray-packed paddy strawmushroom

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wooden cases for transport by rail orboat is practiced in China (Saxena andRai, 1990).

Paddy straw mushrooms can bestored more effectively at the buttonstage than at any other stage. Attemperatures below 100C, however, themushrooms liquefy rapidly,irrespective of the packaging and stageof development (button or umbrellastage), due to chilling injury (Pathaket al., 1998). Figure 13 shows openretailing of paddy straw mushroom inOrissa state of the country where itscultivation has become very popular.

Button mushrooms are packed inmany ways as per the retail, wholesaleand transport requirements. Gormleyand MacCanna (1967) conducted astudy to identify the various qualityattributes of fresh mushroomspreferred by the consumers (Table 5).Two most important quality factorsthat affect the sale of fresh buttonmushroom at the retail shop are the

Fig. 13. Open retail sale of paddy straw mushroom in Orissa

whiteness and stage of maturity i.e.the unopened button stage.

The most common method ofpacking in developing countries likeIndia is small polyethylene orpolypropylene packets containingmostly 200 or 400 g of mushrooms andgenerally these small packets are

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Table 5. Quality factors in freshmushrooms

S. No. Quality factor Consumeremphasis*

1. Whiteness 3

2. Degree of maturity 3

3. Free from viral disease 3

4. Flavour 2

5. Aroma 2

6. Toughness 2

7. Cleanliness 2

8. Size and shape 2

9. Nutritional value 1

* (3= very important, 2 = less important, 1 = notvery important)Source: Gormley and MacCanna (1967)

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market, by the seasonal farmers isadmittedly, primitive: washedmushrooms packed in thin (<100gauge) polypropylene bags, hand-sealed and unlabelled. Of late, someimprovements with respect tolabelling and machine-sealing havebeen introduced. Some firms haveintroduced unwashed mushrooms inplastic trays over-wrapped with PVCfilms; six trays of 200 g each in theprinted card board boxes (Fig. 15).

Fig. 14. Button mushrooms with vegetable vendors

stored for a few days by retailers orconsumers (Fig.14). Quantities morethan this have a tendency to loosetheir acceptability due to price factor.For transportation, these small packsare stacked in large containers (Sethiand Anand, 1976; 1984-85).

Keeping in view the family-demandand price, mushrooms are also packedin plastic punnets (trays) over-wrapped with PVC film. Packaging ofthe button mushrooms for retail

Fig. 15. Unwashed mushroom packed in card board boxes

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Mushrooms need to be packed fortransporting them to the market.Needless to emphasize that while agood pack sells a product, a mediocrepack can adversely affect the sale ofan otherwise excellent product.Saxena and Rai (1988) stored buttonmushrooms in polypropylene bags ofless than 100 gauge thickness withperforations having vent area ofabout 5 per cent and they observedexacerbated veil-opening, browningand reduction in weight during thestorage in the perforated bags keptat 15°C; mushrooms were bestpreserved in non-perforated bagskept at 5°C. They also suggested thatbutton mushroom should be stored inpolystyrene or pulp-board punnets fortransporting to the long distances,instead of using polythene bags.Plastic punnets with size of 130 x 130x 72 mm, cardboard chip of 4 lbcapacity with size of 305 x 125 x 118mm, plastic trays of 5 lb capacity withsize of 400 x 300 x 100 mm, expandedpolystyrene containers of 5 lb capacitywith size of 330 x 280 x 145 mm andexpanded polystyrene container of 10lb capacity with size of 400 x 333 x 167mm packs are used for bulk packagingin the developed countries.

Maaker and Merkens (1969) over-wrapped the mushrooms withmoisture permeable film and foundthat the film retarded wilting withoutcausing accumulation of free moistureon the film and undesirablecondensation. The mushrooms

became waterlogged and discolouredinternally when condensationoccurred inside the package duringstorage (Ryall and Lipton, 1979).Langerak (1972) reported that 600 gchip-board box lined inside with anabsorbent paper and outside withwater-proof paper was one of the bestpacking material for mushrooms. Itwas also observed that mushroomsdiscoloured faster in the PVC-boxeswith the perforated cover than inclosed boxes of chipboard anddesiccation was much less in theclosed cardboard box than in the PVC-box.

Dhar (1992) also found that fruitbodies of summer white buttonmushroom (Agaricus bitorquis) couldbe stored without significant loss ofquality for 6 days at 15°C in non-perforated packs without any chemicaltreatment or washing in water. De laPlaza et al. (1995) found that use oforiented polypropylene (OPP) film candouble the storage period compared toPE film, and maintains mushroomquality for at least 2 days at 18°C.

Other improved packagingsystems especially in the developedcountries are modified atmosphericpackaging (MAP), controlledatmospheric packaging (CAP) andmodified humidity packaging (MHP).Due considerations have to be givenfor other alternatives available likecorrugated fibre board boxes,corrugated polypropylene bond boxes,

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plastic trays, crates, woven sacks,thermoformed plastic trays andstretch film and shrink wrapping.

4.1. Modified atmospherepackaging (MAP)

Modified atmosphere is created ina sealed package of a freshhorticultural produce as a result ofexchange of respiratory gases namelyoxygen (O2) intake and carbon dioxide(CO2) evolution. When the rate of gaspermeation through the packagingmaterial equals respiratory gasexchange, consequently anequilibrium concentration of O2 andCO2 are established. The equilibriumdepends on temperature, respirationrate of specific product, productweight, O2 and CO2 permeabilities ofthe packaging material, free volumein the package and film area (ZakioBano et al., 1997). Properties of thepackaging materials play most criticalrole in modifying the insideatmosphere around the product andconsequently the product quality.

Modified atmosphere can becreated by two methods: active andpassive modifications. In passivemodification, the product is just sealedin a polymeric package and due to therespiration of the fresh produce andpermeation of gases in / out of thepackage, the atmosphere is modified.In passive modification, it takes a longtime to reach the steady-stateconditions within the package. In

active modification, desired gas(es) isinitially flushed into the package, sothat the steady state atmosphere isreached quickly after packaging.

Modified atmosphere packaging(MAP) of mushrooms has been shownto delay senescence and maintainquality of mushrooms during postharvest storage by several workers(Henze, 1989; Burton, 1991; Burtonand Maher, 1991; Briones et al., 1992;Saray et al., 1994; Roy et al., 1995 a;Tano et al., 1999). Mushrooms coveredwith PVC-film resinite had a shelf-lifeof 5-7 days at 15-21°C, as compared tothose left uncovered which had a shelf-life of 2-4 days under similarconditions (Gormley and MacCanna,1967).

The MAP technology for extendingthe shelf life of button mushroomusing modified atmosphere packagewas tried at the Institute ofHorticultural Research,Littlehampton (UK). Theincorporation of a small area of amicroporous film into theoverwrapping film created modifiedatmospheres in mushroom punnetswith moderately low but acceptableoxygen levels. The technique delayedmushroom development and reducedbrowning and incidence of visiblesymptoms of diseases on mushroomsat 18°C storage (Burton, 1988).Nichols and Hammond (1973) packedthe mushrooms in six different typesof films, stored them at two different

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temperatures (2 and 18°C) andevaluated the effect of modifiedatmospheres on the quality. Theyfound that at 2°C, equilibrium wasestablished roughly after 24 h at 4 to10 per cent CO2 and 11 to 17 per centO2; the mean concentration wasdependent on the type of film. At 18°C,equilibrium was established at 8 to 15per cent CO2 and 1 to 2 per cent O2.They suggested that film should bechosen according to the storagetemperature of the product. The poorkeeping quality of mushroom wasmainly attributed to enzyme andmicrobial activity. The high levels ofpolyphenol oxidases present in themushroom reduced the keeping qualityin the presence of oxygen and resultedin discoloration. In absence of oxygen,phenol oxidase activity was reduced andthere was less brown discolouration ofthe cap. An atmosphere containing 5 percent CO2 with or without 1 per cent O2level prevented cap opening ofmushroom up to five weeks at 0°C(Murr and Morris, 1974). Nichols andHammond (1974) reported that 1-4 pin-holes (one mm diameter) in over-wrapping PVC film could control thedegree of modification of theatmosphere. Bush and Cook (1976)reported that the optimum conditionsfor retaining the most acceptable colourand appearance of mushrooms were tostore them in perforated plastic packsat 4-7°C and 40-50 per cent relativehumidity. According to Nichols (1985)the overwrap films should be perforated

to keep the oxygen levels above 4 percent to prevent anaerobiosis.

The punnets over-wrapped withdifferentially permeable polyvinylchloride (PVC) or poly acetate films,created modified atmosphere of about10 per cent CO2 and 2 per cent O2within the punnet during storage.When a combination of microporousand a relatively impermeable film wasused for packing, significant reductionin loss of quality during storage ofbutton mushroom was observed(Burton et al., 1987 a & b; Burton etal., 1989). Burton and Twyning (1989)compared the modified atmospherestorage of button mushroom at theambient (18°C) and lower storagetemperature (10°C and 2°C) andreported that the combination of lowtemperature storage with modifiedatmosphere delayed the post harvestdevelopment of mushroom.

Halachmy and Mannheim (1991)reported that there was no chillinginjury to mushrooms at temperaturesas low as 1.5°C. The respiration rateswere found to decrease withtemperature and reduction intemperature resulted in the bestappearance of mushrooms. Thecritical O2 and CO2 concentration forbest quality were found to be 1.5-2 percent and 12 per cent, respectively.Briones et al. (1993) determined theoptimal atmosphere for storage ofmushrooms and found that CO2

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concentration of 2-5 per cent gave thebest colour. They suggested that 2.5-5per cent CO2 and 5-10 per cent O2 werethe optimum storage conditions formushrooms. On the other hand,Anantheswaran et al. (1994)recommended 4-6 per cent as anoptimum concentration of O2 formodified atmosphere storage ofmushrooms.

Kuyper et al. (1993) investigatedthe effect of modified atmosphericpackaging in combination with theaddition of calcium hypochlorite onthe colour and microbial quality ofmushroom, using differentcombinations of perforated and non-perforated polymeric materials (PVCand LDPE) during storage of buttonmushroom and found that there wasno improvement in colour due tocalcium hypochlorite. It significantlyreduced the microbial counts in thePVC treatment with two perforations.

Roy et al. (1996) found thatincreased in package relativehumidity (IPRH) of 87-90 per centmaintained the best colour in freshbutton mushrooms during themodified atmosphere storage. ChiJeongHyun et al. (1996 & 1998) studiedthe effect of packaging materials(Polyvinylidene chloride coated,oriented nylon, anti-fogging wrap orvacuum packing film) in modifiedatmosphere storage on the keepingquality of mushrooms and found thatthe antifogging film maintained the

quality of mushrooms for 24 days.Gonzalez Fandos et al. (2000) observedthat the non-perforated packages hadthe highest contents of CO2 (6-7 percent), the lowest contents of O2 (0.013-0.17 per cent) and the most desirablequality parameters (texture,development stage and absence ofmoulds).

Singh et al. (2001) observed thatfreezing of mushrooms in liquidnitrogen before storage at subzerotemperature and low temperaturestorage under modified atmospherewith air replaced by nitrogen gas wereeffective in maintaining the shelf lifeof button mushroom for 12 days. ShiQiLong et al. (2004) optimized themodified atmosphere storageconditions for button mushroom andfound that the optimum range ofmushroom diameter was 30-40 mm forMA storage; browning degree could beeffectively reduced by avoidingmechanical injury during postharvest.They found that optimum compositionof package mode was the packagematerials with PE (0.05 mm, anti-fog),80 per cent package content anddrilling two small holes at single sideof package sack.

Wang Xiang You et al. (2004)conducted studies to determine theeffect of chemical fresh-keepingsubstance on the keeping quality ofmodified atmosphere stored buttonmushroom and reported that the bestbrowning inhibitor and concentration

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for stored button mushroom are 0.1per cent sodium sulfite, 0.06-0.10 percent ascorbic acid and 0.8-2.6 mmol/litre cysteine. They also observed thebest constitute and proportion forfresh-keeping substance are 0.15 percent sodium sulfite, 0.05 per centascorbic acid, 12 mmol/litre cysteineand 8 min soaking time.

4.2. Controlled atmospherepackaging (CAP)

As compared to the conventionalMAP (passive modification ofatmosphere within the packs due toproduce and film property), very fewinvestigations have been carried outon the controlled atmosphere package(CAP) i.e. deliberate and activemodification of atmosphere byflushing of gases from outside source.Ramanathan et al. (1992) studied thequality of oyster mushrooms stored indifferent thickness of polyethylenebags under controlled atmospherestorage and found that 300 gauge and150 gauge polyethylene bagsmaintained the keeping quality ofmushroom up to 20 days at 15 per centCO2 and 1 per cent O2 gas composition.Zheng Yong Hua et al. (1994) conductedstudies on controlled atmospherestorage of fresh button mushroomsand found that 8 per cent O2 + 10 percent CO2 was the best atmosphere formaintaining the quality of freshmushrooms.

4.3. Modified humiditypackaging (MHP)

Most polymeric films used in theconventional packing have lowerwater vapour transmission ratesrelative to transpiration rates of thefresh produce, which often leads tonearly saturated conditions within thepackages. The high in-package relativehumidity (IPRH) may causecondensation of water vapour withinthe package and allow microbialgrowth; it also reduces the visibilityof the produce for inspection. Thismay either increase or decrease thespoilage depending on the product’stranspiration coefficients and waterpotentials (Cook and Papendick, 1978).

To obtain the desired IPRH, thereare two possible approaches:perforation of the package, whichprecludes the possibility of achievingthe modified atmosphere conditionswithin the package, and use of in-package water absorbing compounds,like calcium chloride, can maintainthe required IPRH (Eaves, 1960). Royet al. (1996) found that MAP incombination with MHP furtherimproved the shelf-life of freshmushrooms. An IRPH of 87-90 percent was desirable for best colour inmushrooms during storage.

The shelf-life of the mushroomscould be further extended by

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supplementing some chemicals inaddition to modifying the atmosphereinside the package during storage. Useof sorbitol pouches maintained thebest colour in mushroom when it waspacked and stored along with freshmushroom wrapped with PVC films(Roy et al., 1995 b). Anantheswaranand Ravi Sunkara (1996) usedcommercially available food grademoisture absorbers such asmontmorillonite clay and silica geland extended the shelf-life ofmushrooms in modified atmospherepacks.

Cho Sungsan et al. (1998) studiedthe effect of various supplementarypackaging materials (activatedcarbon, chitosan, potassiumpermanganate) on the quality ofmushrooms stored in antifogging filmat the ambient temperature and foundthat chitosan prolonged the shelf-lifeto 10 days, 4 days longer than thecontrol treatment. Popa et al. (1998)studied the use of a humidity absorber(Silica gel) in the packages during themodified atmosphere storage andfound washing in chlorinated waterand incorporation of dehumidifiersdecreased the microbialcontamination and extended the shelflife of Agaricus bisporus.

4.4. Washing

In American and Europeancountries, where peat is used as thecasing soil and sprays are in the

nature of ‘washing down’, themushrooms are not washed beforepackaging. However, in India andsome other countries, buttonmushrooms, which are often soiled dueto the use of FYM-based casing soil,need to be washed before sale orprocessing. Consumers have developeda preference for the washedmushrooms, though enlightenedpeople still go for the unwashed.Though washed mushroomsdeteriorate faster than unwashed butwashing becomes necessary to removesoil particles if non-peat casing soil isused. Mushrooms are trimmed withstainless steel knives immediatelyafter harvesting (Fig. 16) and washedto remove the adhering casing soil andother foreign materials and then theyare packed in suitable containers.Increased water content in themushroom, however, results inshogging and spoilage by bacteria.Generally plain water is used forwashing of the mushrooms, whichmakes the mushrooms free from theadhering casing soil only, but does notimpart any whiteness to themushroom. To improve and maintainwhiteness many pretreatments havebeen tried: dipping of mushrooms indilute solutions of hydrogen peroxide(1:3) for half an hour and thensteeping in 0.25 per cent citric acidsolution containing 550 ppm sulphurdioxide showed significant positiveeffect (Pruthi et al., 1984). Smallgrowers wash the mushrooms insolution of other reducing agents also

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to retard the browning caused bypolyphenol oxidase.

Beelman (1987) reported thatOxine, a stabilized form of chlorinedioxide, was effective in controllingbacterial growth and colourdeterioration of the button mushroomwhen used at a level of 50 ppm orhigher with a two minute or longerwash period. Use of sodiumhypochlorite (100 ppm) and calciumchloride (0.55 %) with oxine (100 ppm)was found to result in increasedantibacterial effectiveness. Use ofcalcium chloride and oxine alsoresulted in lower cap-opening andfirmer mushrooms during the storage.

Maini et al. (1983, 1987) reportedthat washing of mushrooms prior topacking is very important forenhancing the shelf-life and extendingits marketing period. Washing of freshmushroom in water containingsodium sulfite solutions resulted inlower bacterial counts and improved

initial appearance (Fig. 17), but morerapid bacterial growth and browningoccurred during subsequent storagecompared to unwashed controls(Guthrie and Beelman, 1989).Mushrooms washed in hard water (150ppm calcium carbonate) reducedbacterial growth and there was lesscolour deterioration during storagewhile washing mushrooms in asolution consisting of Oxine (50 ppm),sodium erythroborate (0.1 per cent)and calcium chloride (0.5 per cent)resulted in significantly lower

Fig. 16. Harvesting and trimming (stem-cutting) of button mushroom

Fig. 17. Washed button mushrooms

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bacterial populations and less colourdeterioration during subsequentstorage.

Glandorf (1962) reported thatwashing mushrooms in 0.1 per centsolution of potacki (a mixture of saltsof organic acids including citric acid)for 15 min improved their keepingquality and maintained the freshappearance. Gormley (1972) couldprevent discolouration of buttonmushroom by soaking in variousconcentrations of citric acid (0-1 percent), but observed an adverse effecton flavour. Pre storage dips in citricacid (0.05 to 0.1 per cent) used toprevent oxidative browning due to o-diphenol oxidase, led to thedevelopment of typical flavours(Liebster et al., 1975).

Washing of mushroom inchlorinated water and incorporationof dehumidifiers like silica gel in thepacks decreased the microbialcontamination and extended the shelf-life of button mushroom (Popa et al.,1998). The washing treatmentconsisting of 1000 ppm chlorine incombination with 10000 ppmhydrogen peroxide had potential as analternative to the use of sulphite inthe washing of mushrooms(McConnell and Beelman, 1994).Hershko and Nussinovitch (1998)coated the button mushrooms withdifferent gum-based coatings,including alginate and alginate-ergosterol, with and without

emulsifier. They found that coatedmushrooms had better appearance,colour and an added advantage inweight retention in comparison to theuncoated ones. The alginate-ergosterol- Tween coatingcombination was most suitable formaintaining the size, shape andquality of the coated mushroom.Sapers et al . (1999) found thatwashing of button mushroomsdamaged the surface structure,which promoted microbial growth.Washing with 5 per cent hydrogenperoxide (H2O2) extended shelf-lifefrom 4-6 days to one week but itinduced browning. Washing with 5per cent H2O2 followed by applicationof sodium erythorbate controlled thedevelopment of browning (Sapers etal., 2001). Czapski (2002) reported thebest results by dipping mushrooms inhydrogen peroxide solution (1st stage)and then in solution consisting ofsodium erythorbate, cysteinehydrochloride and EDTA. Saxena andRai (1988) observed that washing ofmushrooms in 0.05 per centpotassium metabisulphite improvedthe initial whiteness which lastedlonger during the storage. EDTA(disodium) has also been found to givegood results in washing of mushrooms(Ahlawat et al., 2000 a). The calciumchloride added to the irrigation waterimproved the quality and shelf life ofbutton mushroom (Barden et al., 1990;Solomon et al., 1991; Miklus andBeelman, 1994; Simons et al., 1995 a;Miklus and Beelman, 1996; Ahlawat

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et al., 2000 b) and also the yield andcolour of the canned mushrooms(Simons et al., 1995 b). Sharma andBahukhandi (2003) obtained the bestresults in terms of maintenance offruiting body quality by washing withKMS, tartaric acid and ascorbic acidat 12±20C.

4.5. Transportation

The positive effects of pre-coolingand packing will be partiallyneutralized if the product thereafter

is stored and transported in a hotenvironment. Mushrooms, thereforeneed complete cool-chain for storageand transport. To keep the precooledmushrooms cool during the transportto the short distances under theambient conditions, the polypacks ofmushrooms are stacked in smallwooden cases or boxes with sufficientcrushed ice in polypacks (overwrappedin paper) by the small growers. Fortransport of the large quantities to thelong distances, refrigerated trucks,though costlier, are indispensable.

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All techniques which storemushrooms, processed orunprocessed, longer than normalstorage period for the fresh aretogether called long-term storage. Dueto the improved strains, productiontechnology and innovative techniquesmushroom production in our countryhas increased over the years. Need forlong-term storage may not ariseduring the off-season, but, tominimise the fall in prices in the peakseason and also to avail the high priceduring the off-season, the grower andprocessors preserve them by differentmethods to extend the shelf-life andadd value to the product. This long-term stored mushroom can beexported as well as made availableduring the off-season. Commonlyfollowed long-term storage techniquesfor mushrooms are canning, drying,steeping and pickling.

5.1. Steeping preservation

Cost of the canned and freeze-driedmushrooms is very high and not manycan afford such products. Steepingpreservation of mushrooms (Bano andSingh, 1972; Adsule et al., 1981; Pruthiet al., 1984; Sethi et al., 1989 & 1991;Sandhu and Aggarwal, 2001) isconvenient as well as economical forextension of the shelf-life of

mushrooms and also for transportthis highly perishable commodity tothe distant places. The method issimple, economical and mushroomscan be preserved for periods rangingfrom 3-6 months by steeping them inconcentrated solutions of salts and oracids. Steeping preservation ofmushrooms helps to extend shelf lifeas well as retain whiteness. Cleanedmushrooms are washed in plain wateror chemical-added water and filled inlarge plastic containers. Five minutesblanching in brine solution is sometimes done before filling them incontainers. Brine solution is thenadded into the cans or containers. Thesteeped button and oyster mushroomsare shown in Figure 18.

Various researchers have trieddifferent chemical cocktails forsteeping preservation. Solutionconsisting of 2 % sodium chloride, 2% citric acid, 2 % sodium bicarbonateand 0.15 % KMS (Kapoor, 1989) and of2 % salt, 2 % sugar, 0.3 % citric acid,0.1 % KMS and 1 % ascorbic acid(Singh et al., 1995) were used forsteeping preservation of the blanchedbutton mushrooms for 8-10 days at 21-280C. Dipping of mushroom in dilutesolutions of hydrogen peroxide for halfan hour and then steeping in 0.25 percent citric acid solution containing


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550 ppm sulphur dioxide hadsignificant effect on the whiteness ofmushroom (Pruthi et al., 1984). Singh(1997) demonstrated that cream whitecolour of button mushroom can beretained and their shelf life extendedup to 375 days under the ambientconditions by steeping preservation.He washed mushrooms for one min inwater, blanched them for 3 min inboiling 2 per cent NaCl and steeped ina solution of 5 per cent NaCl + 1 percent sugar + 0.3 per cent citric acid +0.5 per cent ascorbic acid + 1000 ppmKMS. Huawang and Cheng (1978)conducted studies on mushroomstreated with salt and organic acidsand reported that salt concentrationhigher than 10 per cent intensified thebrowning reaction of the mushroom

but when the cover-brine wasequilibrated at pH 4 with organicacids, no further browning wasobserved. Treatments of mushroomswith higher concentrations of organicacids, however, reduced the hardnessof mushrooms.

This type of preservation can bedone by two methods.

5.1.1. Unexhausted steepingpreservation

Fresh mushrooms were washedand blanched in 0.05 per cent of KMSfor 5 min. After draining off,mushrooms were washed with coldwater for 4-5 times and then filled inthe bottles or cans. Hot brine of 18 to

Fig. 18. Steep preserved button and oyster mushroom

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20 % NaCl and 0.1 % citric acid wasfilled in the bottles. After properlidding, the bottles were kept forstorage at room temperature. Thismethod of steeping preservation isknown as unexhausted steepingpreservation and was good for storingmushrooms upto 3 months (NRCM,Annual Report-2000-01).

5.1.2. Exhausted steepingpreservation

Upto filling of the brine solutionin the bottles, the procedure is sameas described above. After filling thebrine+acid solution, the bottles arekept in hot water bath until thetemperature of brine reaches 80 to850C in the center. After maintainingthe brine temperature at 850C for 10min, the bottles are sealed and keptfor storage (NRCM, Annual Report-2000-01). Only water-blanchedmushrooms impart yellow colour tolesser degree and whiteness ismaintained excellently in the treatedmushrooms (Pruthi et al., 1984).

To consume the steep preservedmushroom, it has to be thoroughlywashed (debrined) with water andthen it can be used as per requirement.The technique has also been toaccumulate the quantities sufficientfor a batch of canning as well as fortransporting steeped mushrooms tolong distances by shipping, forcanning.

5.2. Drying

Drying is perhaps the oldesttechnique known to the mankind forpreservation of food commodities forlong duration. It is the process ofremoval of moisture from the productto such a low level that microbial andbiochemical activities are checked dueto reduced water activity which makesthe products suitable for safe storageand protection against the attack bymicroorganisms during the storage.Mushrooms contain about 90 per centmoisture at the time of harvesting andare dried to a moisture level downbelow 10-12 %. At a dryingtemperature of 55-600C, the insectsand microbes on the mushrooms willbe killed in a few hours, which givesus the dehydrated final product oflower moisture content with longershelf-life. The temperature, moistureof the mushroom and humidity of theair affect the colour of the driedproduct (Yapar et al., 1990).Dehydrated mushrooms are used as animportant ingredient in several foodformulations including instant soups,pasta, snack seasonings, casseroles,and meat and rice dishes (Tuley, 1996;Gothandapani et al., 1997).

Most of the mushrooms, except thebutton mushroom, have beentraditionally dried for long-termstorage e.g. oyster, shiitake, paddystraw, Auricularia etc. In case ofbutton mushroom it is the blackening

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and irreversible change of texture,which often discourage the use of thisotherwise simple technique ofpreservation.

5.2.1. Sun-drying

Sun-drying is the cheapest andoldest method among various dryingmethods. It is a very simple operation,where no fuel or mechanical energy isrequired. However, it is completelydependent on weather and it is notpossible round-the-clock and round-the-year. Even though the quality ofthe product is affected by theenvironmental factors, due to freeavailability of heat source, it isconsidered to be the lowest-costmethod of drying. Mushrooms arespread over the trays or sheets andkept in open under the sun; favourableatmospheric conditions are above250C temperature, with less than 50per cent relative humidity and highwind velocity. Sun dried productcontains more than 10-12 % moistureand should therefore be oven dried at55-600C for 4-6 h to further reduce themoisture to 7-8 % to avoid any spoilageduring storage. The dried productregains to a large extent its flavourand texture after rehydration. Thetechnique has however, been not usedfor the button mushroom. Othermushrooms are generally sun-dried byresource-poor growers (Rai et al.,2003). Saxena and Rai (1990) reportedthat dhingri could be sundried duringthe days with high temperature (above

250C), low humidity (less than 50percent RH) and high wind velocity.The fruit body of the dhingri can bebeaded in a thin wire or thread andhanged in the air in direct sunlight forefficient dehydration and freenessfrom dust. The weight of the endproduct of this method had 10-12percent of its original weight. Theyalso recommended that the sundriedproduct should be oven dried at 55-600C for 4-6 h before packing in air-tight packs.

Rama and John (2000) reportedthat when the temperature duringsun-drying ranged from 21.60C to35.70C, time taken was 14 h for thepretreated oyster mushroom and 12 hfor the untreated oyster mushroom, toreach 5-6 per cent moisture level. Theyalso reported that the dehydrationratio, shrinkage ratio and rehydrationratio of the sun dried product (Fig. 19)was 10.64, 0.19 and 2.21 respectively.The colour of the final product variedfrom brown to creamy white.

Fig. 19. Sun-dried oyster mushroom

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Nehru et al. (1995) designed anddeveloped a solar mushroom drierwith a capacity of 2.5 kg fresh oystermushroom / day. The oystermushrooms treated with 0.5 per centKMS for 15 min and 0.5 per centsodium benzoate for 15 min had thesame amount of nutrients (protein,sugars and amino acids) as freshmushrooms. The highest rehydrationratio (5.25) and best organolepticquality was obtained for the sampletreated with 0.5 per cent KMS.

Sugana et al. (1995) conductedtrials with a natural convection solarcabinet drier for drying oystermushroom and it took a drying timeof 7 h when the ambient temperaturevaried between 29 and 320C.Arumuganathan et al. (2004)conducted the experiments on sun-drying of oyster mushroom and foundthat the treatment with 0.05 % KMS+ 0.1 % citric acid yielded good qualitydried oyster mushroom.

5.2.2. Cabinet air drying

Cabinet air drier which is alsoknown as tray-drier (Fig. 20) consistsof series of trays placed in the plenumchamber and hot air at constant airflow rate is allowed to pass throughthis plenum chambers.

However, the conventional oven-drying method results in dark browncoloured product with a tough texturein case of the button mushroom; other

mushrooms give reasonablyacceptable product. Due to little airmovement inside the conventionaloven, the evaporated water condenseson fruit bodies increasing themucilage and deteriorating thequality. Large quantity of condensedwater may also damage the equipment.Hence, a cabinet drier with circulatedair supply was found to be superior(Mudahar and Bains, 1982). Thisprocess utilizes mechanical means forventilating natural/hot air throughmushrooms to accomplish theremoval of moisture. Its features are

1. The rate of drying can becontrolled by adjusting thetemperature of hot air ventilatingthrough the mushroom. Theprocess, therefore, makes possiblethe reduction of temperature andmoisture stress developed duringthe drying process.

2. Mushrooms can be driedirrespective of weather conditions,

Fig. 20. Cabinet drier

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day or night, as the process doesnot depend on any natural sourceslike sunlight.

3. The process is automatic andrequires unskilled labour except atrained person to operate thedryer.

4. There are practically no losses toinsects, birds and rodents in theprocess.

5. It, however, requires fuel andelectrical or mechanical power todrive the air blower, elevators etc.therefore the cost of drying per kgof mushroom is higher comparedto sun drying.

6. It requires less space foroperation.

The drying temperature of 550C inthe plenum chamber has been foundto give the end product with thedesired qualities of texture, colour andrehydration. Home made cabinet drieris essentially a galvanised box of size90 x 60 x 90 cm with perforated ironsheet at the bottom. The sides and thetop of the box are fixed in a woodenframe and the whole thing is supportedon an angle iron stand of about 38 cmheight. There are two slits (5 cm x 3.7cm) along the top end of the two longsides and about 10 cm below the top.These slits are provided with metallicshutters for opening and closing.About seven trays (87 cm x 60 cm) can

be stacked on supports in staggeringpositions. The perforated iron plateat the bottom of the cabinet can beheated by means of a charcoal oven oroil stove.

Bano et al. (1992) reported that themechanically-dried oyster mushroomspacked in air-tight containers havemore than one year of shelf-life. Ramaand John (2000) studied themechanical drying of oystermushroom. They maintained thetemperature at 600C for the first 4 hand later at 500C for the rest of the 11h of drying to reach a moisturecontent of 5-6 per cent except thesamples without any pretreatmentwhich took only 8 h. The dehydrationratio, shrinkage ratio and rehydrationratio of the mechanically driedproduct were 9.89, 0.2 and 2.61respectively. The colour of the driedproduct varied from brown to creamywhite. Dehydrated oyster mushroomsshould be packed in foil-laminatedpouches for better storage stability(Kumar et al., 1980). Figure 21 showsthe picture of the cabinet dried oystermushroom.

Conditions of dehydration oftropical paddy straw mushrooms havebeen standardized by Pruthi et al.(1978). For the inactivation ofperoxidase and catalase prior todehydration of mushrooms, optimumtime of water blanching was found tobe 3-4 min and that of steam blanchingas 4-5 min. Dehydration process in a

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cross-flow drier at 60°C took about 8h, while dehydration in a phasedmanner at 70-65-60°C took about 7 h.Authors recommended a three-phasedehydration process, which is asfollows: initial drying temperature of70°C for 2 h followed by 65°C for 2 hand 55-60°C for the rest of the time.

Thickness of mushroom is animportant factor affecting the dryingcharacteristics; other factors aretemperature and ratio of the air-filmto mushroom resistance towardswater diffusion. Pruthi et al. (1984)reported that longitudinally sliced andblanched button mushrooms whendried at 600C for 5 h, had a drying ratioof 10.8:1 and rehydration ratio of 2.78as against cross slit mushrooms withdrying time of 8 h, drying ratio of10.9:1 and rehydration ratio of 2.80.According to Arora et al. (2003),blanching of both button and oystermushroom in boiling water for onemin and treating in solution

containing 0.1 % citric acid and 0.25% KMS for 15 min at roomtemperature resulted in lowestbrowning index and the activationenergy values of button and oystermushroom were determined to be19.79 and 23.59 kJ/mol in the cabinetdrying method. Pandey et al. (2002)conducted dehydration studies onmilky mushroom and observed thatrehydration of oven-dried product wasbetter than room temperature or sun-dried samples.

Drying in mechanical dehydratorwas reported to be fastest by Katiyar(1985) because of high air temperatureand forced air circulation. Meandehydration time was 8.4 h where as16.8 sun hours were needed in sun-drying. However, Ashwani Kumar(1992) dehydrated Agaricus bisporusfor 9 h at 60±20C to a constant weight.Lidhoo and Agrawal (2006) dried whitebutton mushroom in a hot air oven andobserved that minimum browning

Fig. 21. Cabinet air-dried oyster mushroom

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index was recorded at 650C andrehydration ratio obtained at thistemperature was 2.9.

5.2.3. Dehumidified air-cabinetdrying

Dehumidified air-cabinet drying isaccomplished by dehumidifying aircabinet drier (Fig. 22). The principle

in which this drier works is shown inFigure 23. Ambient air is passedthrough an air heater and gets heatedup. Hot air passes into the dryingcabinet and removes moisture fromthe mushroom. Air gravitates to or /is sucked onto the condenser (chiller)where it deposits its moisture. Theother type of dehumidified air dryingis to expose the moisture-laden air topass through the desiccated mediumeg. Silica gel. The desiccator (silica gel)absorbs moisture from the air, as aresult, relative humidity of air isreduced and at the same time there isan increase in its temperature. Whensuch dehumidified air comes incontact with fresh mushrooms,transfer of moisture from mushroomto drying air takes place faster (Sahayand Singh, 1994). Figure 24 shows thepicture of excellent oyster mushroomsdried by dehumidifying-air cabinetdrying method. The process allowsfaster drying at relatively lowertemperature as compared to the

Fig. 22. Dehumidifying air cabinet-drier

Fig. 23. Working principle ofdehumidifying air cabinet-drier

Fig. 24. Dehumidifying cabinet air-driedoyster mushroom

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conventional cabinet-air drying e.g. itis possible to dry button mushroomslices and oyster mushroom (whole) at450C or even lower in dehumidifyingair cabinet drier to give superiorproduct (NRCM, Annual Report-2004-05).

5.2.4. Osmo-air drying

Osmotic dehydration is a noveltechnique suitable for high-moistureand perishable commodities viz., fruitsand vegetables. It is a two-stageprocess: first step consists of keepingthe material in a concentrated saltsolution called osmotic syrup; in thesecond stage, a stable dehydratedproduct will be produced after doingproper air drying of the product takenout of the osmotic syrup. Mainprinciple involved in the osmoticdehydration is removing moisture atlower temperatures avoiding thermaltreatments to get a product withcolour, flavour and textural qualitiesnearest to the natural one (Amuthanet al., 1999). Yang and Le Maguer(1992) conducted studies on osmoticdehydration of the button mushroomin a continuously circulatedcontacting reactor and recommended15 per cent NaCl as the optimum.Pretreatments of the mushrooms inhigh concentrations of sucrose,followed by high salt concentrationwas most effective method to removewater and loading salt to further lowerthe water activity in the mushroom.Kar and Gupta (2001) reported that

osmosis using 15 per cent brinesolution could remove about 35 percent of initial moisture in one hour.Amuthan et al. (1999) conductedstudies on osmo-air drying of milkymushroom (Calocybe indica) and foundthat the moisture removal was higherby osmosis at 25 per centconcentration of salt in 6 h duration.The osmosed samples took about 170min to dry and the rehydration of themushroom osmosed with 25 per centsalt concentration was obtained in ashorter period of 50 min. The colourof the osmo-air dried sample was verygood as compared to the cabinet-drying.

Fig. 25. Osmo-air dried button mushroom

5.2.5. Freeze-drying

Removal of water from a substanceby sublimation from the frozen stateto the vapour state is known as freeze-drying. Freeze-drying takes place inthree stages: water present in theproduct is removed by formation of icecrystals; the ice crystals are then

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removed from the outer surface of thematerial by sublimation; after removalof all the ice, the little quantity ofwater left is then removed byevaporation in the freeze dryer (Fig.26). In a freeze-drying system, originalshape and size can be retained and theshrinkage, which is a problem withother drying methods, is almostnegligible.

is very similar to fresh mushroomsbut as the product is brittle, it ispacked in sturdy packings andcushion-packs flushed with nitrogenfor better keeping quality (Saxena andRai, 1990). The product can be storedupto 6 months without any change inits quality and appearance. However,this is a very costly and energy-intensive process and the venturedepends upon the demand and price forsuch products.

Fig. 26. Laboratory freeze drier

Mushrooms are freeze dried at -200C and the moisture is removed bysublimation at a very low vacuum(0.012 mbar) for 12-16 h. The freeze-dried mushrooms (Fig. 27 & Fig. 28)have superior flavour and appearancebut are brittle (Kapoor, 1989). Theappearance of freeze dried mushrooms

Fig. 27. Freeze dried button mushroom

Fig. 28. Freeze dried oyster mushroom

Freeze-drying has been tried by thefollowing method also. The slicedmushrooms are immersed in asolution of 0.05 per cent KMS and 2per cent salt for about 30 min. The

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pretreated mushrooms are thenblanched in boiling water for two minfollowed by cooling. The product isfrozen at -220C for one min. The frozenmushrooms are dried to moisturecontent of 3 per cent in a freeze drierand packed under vacuum (Kannaiyanand Ramsamy, 1980).

5.2.6. Fluidized-bed drying

Fluidized-bed drying is the processof removing moisture by exposingcommodities into a high velocity of hotair. The velocity of the hot air shouldbe such that it should not throw outbut keep the material in the fluidizedcondition. Fluidized-bed drying,besides providing high qualityproduct, reduces drying time also. Alaboratory model fluidized bed drieris shown in Figure 29, the cap is yetto be placed on top of it.

Singh et al. (2001) studied thedrying characteristics of the fluidized-bed drying of the button mushroomand found that quality of thedehydrated mushrooms wassignificantly influenced by thepretreatments as well as temperature;the samples treated with 1 per centKMS, 0.2 per cent citric acid and 3 percent salt solution and dried at 500Cgave satisfactory results. Suguna et al.(1995) designed a batch type fluidized-bed drier of 6 kg / batch capacity andobtained a satisfactory shelf-life of 5months. The optimum temperaturewas found to be 500C with an air flowrate of 35 m3/ min. Figure 30 showsthe picture of the oyster mushroomsdried using fluidized bed drier.

Fig. 29. Fluidized bed drier

Fig. 30. Fluidized bed dried oystermushroom

Deshpande and Tamhane (1981)dried paddy straw mushroom usingfluidized bed drier and found thatdrying at 800C took 90 min to obtainacceptable paddy straw mushroom.

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Further, they observed that driedpaddy straw mushrooms stored athigher temperature (370C) and higherrelative humidity developed off-flavour while samples stored at 250Ctemperature and relative humidity ofless than 60 per cent remainedacceptable upto 2 months.

5.2.7. Microwave drying

Increasing demand for foods thatoffer greater convenience inpreparation and are time-saving haveforced the food processors andconsumers to go for microwave-drying. It offers the products withgood organoleptic and nutritionalvalues (Sahni et al., 1997). Microwavesare generated by magnetron, a devicethat converts electric energy at lowfrequencies into an electromagneticfield with centers of positive andnegative charge that change directionbillions of times per second.Penetration and heating of foods bymicrowave energy sources areinstantaneous. In contrast,conventional heating methodstransfer thermal energy from theproduct surfaces towards the center10 to 20 times more slowly. In amicrowave oven, the product isexposed to an alternatingelectromagnetic field in frequencyrange of 800 to 3000 MHz. This regionof electromagnetic spectrum fallsbetween the frequencies associatedwith radio-waves and infrared

radiation. Two frequencies areemployed for generation ofmicrowaves to prevent interferencewith radio communication or radarequipment; these are 896 MHz and2450 MHz. The microwave energy isinjected with a resonant cavity inwhich the target material is placed orpasses through. Uniformity isachieved by rotating the product or bystirring the incoming microwaves bymoving a deflector into the beam.Microwave radiation, by nature of itsposition in the electromagneticspectrum is non-ionizing and thereforenot capable of producing the long-termeffects on the body associated withother types of radiation (Sahni et al.,1997). However, use of microwaveheating for a complete drying processis likely to be uneconomical(Bengtsson and Ohlsson, 1986), but itmay be advantageous to specifymicrowave heating for use duringfallen period of drying operation wherethe heat and mass transfermechanisms during conventionaldrying are rate limiting (Funebo andOhlsson, 1998; Torringa et al., 2001).The mushrooms when dried withcombined hot air-microwave lead tofurther shortening of the process timeand good quality final product areachieved. Moreover, retention of thecharacteristic aroma compound (1-octen-3-ol) and its oxidation product(1-octen-3-one) are positively affectedby microwave drying (Singh et al.,1995).

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The first commercial applicationof microwave energy in foodprocessing was drying of potato chips(Decareau, 1984). Rama and John(2000) dried the oyster mushroomsusing a microwave oven of T-23 TouchElectronic model. The power outputwas 700 Watts with microwavefrequency of 2450Hz. Three stagedrying was given to the mushroomduring microwave drying, where theinitial power level as 100 per cent for20 min, followed by 60 per cent foranother 20 min and 50 min for the restof the period of drying. It was foundthat the pretreated fresh oystermushrooms took 90 min drying timeto reach 5-6 per cent moisture contentand the mushrooms without anypretreatment took only 75 min toaccomplish 5-6 per cent moisturecontent. Spices and condiments maybe added prior to, during or aftermicrowave drying of the mushroomsfor making ready-made snacks likemushroom chips from slices of button,paddy straw or whole oystermushroom (Unpublished NRCMwork).

5.3. Pickling

Preservation of fruits andvegetables by pickling is age-oldmethod, second perhaps only to sun-drying and are very popular in India.Several recipes of pickle preparationin oil or vinegar are in practice indifferent parts of the country(Girdharilal et al., 1967). Pickling is a

method of long-term storage topreserve mushrooms in aneconomically viable way. Thesepickles are good appetizers as well asthey add palatability to the meal. Itis also a process by which one canstore to relish them during the off-season when the price of mushroomsis very high.

Mushrooms for pickling are eitherblanched or fried in oil till browndepending upon taste; variouscondiments as per local preferencesand practices are also ground or friedin oil separately and added to themushroom. The contents are mixedthoroughly and cooked slightly for fewminutes. It is allowed to cool and thenfilled in the jars (lugs) of desired size.Vinegar may be added for taste andlonger storage and the contents in thebottle or the container should betopped up with oil (Saxena and Rai,1990).

According to a formulationdeveloped and standardized at theNRCM, Solan, mushrooms arewashed, sliced and blanched for 5 minin 0.05 per cent KMS solution. Theblanched mushrooms are washed incold water for 2-3 times and the excesswater is drained off. Then themushrooms are subjected to saltcuring process, in which 10 per centsodium chloride is added and kept overnight. The excess water oozed-out ofmushroom is removed on the next dayand spices & preservatives are mixed

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to the desired taste and quality ofmushroom pickle. The various spicesnamely turmeric powder, blackmustard seed powder (rai), red chillypowder, cumin seed powder, fenugreekseed powder, aniseed powder (suwa/shopa), black pepper, carom seed(ajwain), nigella seed (kalonji), fennelseed powder (saunf) and mustard oilare added to prepare tasty pickle (Fig.31). Acetic acid and sodium benzoatewithin the permitted limits are usedas preservatives.

Fig. 31. Button mushroom pickle

The process flow chart for thepreparation of mushroom pickle isshown in Figure 32. This pickle canbe stored upto one year in the lugbottles (Saxena and Rai, 1990). Thevarious ingredients required forpreparing mushroom pickle using 1 kgblanched mushroom are listed in Table6.

Good quality pickle can also beprepared from oyster mushroom(Arumuganathan et al., 2003). In apatented pickling process, cleanedmushrooms are blanched in hot water

(800C for 5 min), rapidly cooled andadded to 60 per cent brine to obtainmushroom to brine ratio of 7:3 by

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Table 6. Ingredients for mushroom pickle

S.No Ingredients g/kg

1 Black mustard seed powder (rai) 35

2 Turmeric powder 20

3 Red chilly powder 10

4 Cumin seed powder 1.5

5 Fennel seed powder (saunf) 1.5

6 Carom seed (ajwain) 10

7 Nigella seed (kalonji) 10

8 Oil 200 ml

9 Salt 90


Washing (0.05 % KMS)�

Slicing (4 parts)�

Blanching (5-8 min with 2 % salt +0.1 %citric acid)

�Mixing of salt with blanched mushroom

�Treating for over night

�Removal of oozed-out water from


Mixing of acetic acid, sodium benzoateand spices with treated mushroom

�Mushroom pickle

Fig. 32. Flow chart for mushroom picklepreparation

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volume. The mixture is maintained at15-200C for 15 days for fermentationand further kept at 0-40C to obtain apH of 3.9. Sugar is added to thepreparation at the rate of 3.3 per centby weight to the brine and final saltconcentration reached to 6.6 per centby weight (Singh et al., 1995). Singhand Bano (1977) studied the suitabilityof Pleurotus spp. for picklepreservation. They reported that theproduct could be stored for a minimumperiod of 6 months at the ambienttemperature (22-340C) without any offflavour. Khader and Pandya (1981)prepared a pickle from paddy strawmushroom having good keepingquality.

5.4. Canning

Canning is technique by which themushrooms can be stored for longerperiods up to a year and most of theinternational trade in mushrooms isdone in this form. The canningprocess can be divided into variousunit operations namely cleaning,blanching, filling, sterilization,cooling, labeling and packaging. Inorder to produce good quality cannedmushrooms, these should be processedas soon as possible after the harvest.In case a delay is inevitable,mushrooms should be stored at 4 to50C till processed. The mushroomswith a stem length of one cm arepreferred and are canned whole, slicedand stems-and-pieces as per demand(Beelman and Edwards, 1989).

Longitudinal (mushroom shape)slicing is common (Mudhahar andBains, 1982; Pruthi et al., 1984).

5.4.1. Cleaning

The mushrooms are sorted toremove diseased, damaged, bruisedand browned ones. Fresh mushroomswhite in colour, without dark marksin either cap or stem are preferred forcanning. The veil should be in tightclosed condition and not stretchedotherwise the mushroom will open inthe blanching and will be rejected incan-filling process. Grading based oncap diameter is also followed (Azad etal., 1987). Then the whole mushroomsare washed 3-4 times in cold runningwater to remove adhering substances.Use of iron free water with 0.1 per centcitric acid prevents discolouration.Hydration with jets before blanchingis now a common practice in theindustry; it washes as well as hydratesthe mushrooms to reduce weight-lossin canning.

5.4.2. Blanching

Blanching is normally done toinhibit polyphenol oxidase enzymeactivity and to inactivatemicroorganisms. It also removes thegases from the mushroom tissue andreduces bacterial counts. Themushrooms are blanched in stainlesssteel kettles filled with a boilingsolution of 0.1 per cent citric acid and1 per cent common salt. The blanching

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weight respectively are preferred(Saxena and Rai, 1990). However, forexport A-10 (3 kg with drained weightof 1.96 kg) is preferred. The cans arethoroughly washed to remove anyadhering dust or foreign matter. Allthe cans are sterilized before use.Mushrooms can be filled in the canseither manually or mechanically incase of automatic can fillingmachines.

Brine solution (2 % salt with 0.1 %citric acid or 100 ppm ascorbic acid)is added to the mushroom-filled cansafter bringing its temperature to 900C.After filling, the cans are exhaustedby passing them in exhaust box for 10-15 min (length of exhaust box coupledwith speed of conveyor takes care), sothat the temperature in the centre ofthe cans reaches upto 850C. Then thecans are sealed hermetically withdouble seamer and kept in upsidedown position. Azad et al. (1987)recommended a brine solution with 2% common salt, 1 % sugar and 0.05 %citric acid for filling the cans for betterresults. Adsule et al. (1983) suggesteda novel double purpose preservationof tomato juice in place of brinesolution for canning of mushrooms;unlike brine solutions there is no needto add citric acid to tomato juice forlowering the pH of the filling medium.Further, the nutrients of themushrooms could be retained in thetomato juice for human consumption.Arumuganathan et al. (2004 a)obtained improved quality of the

time ranges from 5-6 min at 95-1000C(Tanga, 1974; Saxena and Rai, 1990).Some plants blanch the mushrooms inslightly acidified water to improve thecolour of the canned product. The foamdeveloped during blanching should beremoved constantly. The loss ofweight during blanching is about 20-25 per cent of the fresh weight of theproduct. If blanching time is reducedto restrict weight loss, the loss ofweight at sterilization will beaccordingly higher. Six minuteblanching is common to give properdrained weight of the final productespecially in A-2½ cans. Over-blanching can cause poor quality ofcolour and texture with loss of freeamino acids and sugars (Lal Kaushaland Sharma, 1995). Differentblanching times should be used for thevarious sizes to prevent over-blanching and shrinkage. A shortspray of cold water should follow theblanching process to cool themushrooms to 360C or lower.

5.4.3. Filling

The mushrooms after blanchingare manually filled in tin cans; it takescare of the rejection of mushroomsbroken and opened during blanching(rejection is almost 10 % of the originalweight). The size of the can dependson the amount of produce to be filledin them as per the requirements of thecustomer. In our country generally A-2½ and A-1 tall can sizes containingapproximately 440 and 220 g drained

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canned button mushroom when themushrooms were pre-treated withEDTA.

5.4.4. Lidding or Clinching

The cans after being filled arecovered loosely with the lid and passedthrough exhaust box. In large-scaleprocess, this has certaindisadvantages such as spilling of thecontents, toppling of the lids etc.Lidding has now been modernized bythe clinching process in which the lidis partially seamed to the can by asingle first roller action of a doubleseamer. The lid remains sufficientlyloose to permit the escape of dissolvedas well as free air from the contentsand also the vapour formed during theexhaust process.

5.4.5. Exhausting

Before sealing, it is necessary toremove all air from the contents. Theprocess by which this is achieved isknown as exhausting. By removing air,risk of corrosion of the tin plate,pinholing during storage anddiscolouration of the products arereduced; because oxidation isprevented. To be effective, thetemperature of the brine in the canshould be at least 800C. Removal of airalso helps in better retention ofvitamins, especially of vitamin C. Theexhausting process will also assist inavoiding overfilling or underfilling ofcan, which normally happens due to

the tendency of expanding orshriveling during heating. The otheradvantages of the exhaust process are:prevention of bulging of the can whenstored at high altitudes or in hotclimates, reduction of chemicalreaction between the container andcontents; and prevention of excessivepressure as well as strain duringsterilization. Cans are exhausted inthe exhaust box where filled cans arepassed through a hot steam at about1000C on a moving chain conveyorthrough a covered double jacketedsteam box. The time of exhaust variesfrom 10 to 15 min. At the end of theexhaust box, the temperature at thecentre of the can should be about 800C.

5.4.6. Sterilization

Sterilization is the process ofheating the cans to prevent thespoilage by microorganisms duringstorage. Saxena and Rai (1990)mentioned two procedures for commonsterilizing of the cans:

a) A continuous process called‘steriflame’ in which cans aretreated by passing them over gasburners. This process lasts for 3-8 min.

b) A batch process, in which the cansare placed in an autoclave andsterilized for 25-30 min, under 15lb/sq inch (1.06 kg/sq cm) (time andpressure varies with can andmushroom size).

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The sterilization temperatureshould not be above 1180C to avoiddiscolouration and burnt taste.

5.4.7. Cooling

The cans are cooled immediatelyafter sterilization process to stopover-cooking and to prevent stack-burning. Cooling can be done byplacing the cans in a cold-water tank.It also gives an abrupt shock to themicroorganisms to get rid of theiradverse activities.

5.4.8. Labeling and Packing

The outer surface of the can shouldbe completely dry as even small tracesof moisture are likely to causerusting. The clean and dry cans arelabeled manually or mechanically andpacked in strong wooden crates or

corrugated cardboard cartons. Thecans are stored in a cool and dry placebefore dispatch. In a hot country likeIndia, where the ambienttemperatures are high during severalmonths in a year, basement stores areuseful, especially during the summermonths. Figure 33 shows the differenttypes of cans and canned buttonmushroom (whole and sliced).

Very high loss in weight of themushrooms is the most seriousproblem in the canning. This is alsoknown as ‘shrinkage’, which is causedby the removal of water as well assolids from the mushrooms duringprocessing operations. The losses varyfrom 35-40 per cent and seriouslyaffect the profitability of the cannery.To ameliorate this problem, variousmethods have been tried to varieddegrees of success. Water bindingadditives viz., sodium polyphosphate,sodium alginate, Agar-agar, methylcellulose, carboxy methyl cellulose,pectin and pectin-calcium chloridehave been used by various workers inincreasing the drained weight(reducing the shrinkage) of cannedproducts (Singh et al., 1982). Theshrinkage losses can also be decreasedby the vacuum treatment of the freshmushroom, cutting the blanchingtime and also prehydrationtreatments. The level of the vacuumachieved and the quality of themushroom will affect the shrinkagelosses of 5 to 10 per cent (Steinbuch,1978). Kapoor (1989) documented a

Fig. 33. Canned button mushroom(Can sizes- 8 Ounce, A-1 tall, A-2½, A-10,

wholes and slices)

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standardized canning process andrecommended steam blanching for lowloss in weight. Figure 34 shows thecanned paddy straw mushrooms in themarkets of Orissa.

Fig. 34. Canned paddy straw mushroom

order to maintain the desired weightin the final product, the commonindustry practice is to reduce majorportion of shrinkage during theblanching operation and thusminimize the shrinkage duringthermal processing of the cannedmushrooms. Konanayakam et al.(1987) developed a method todetermine the shrinkage ofmushrooms during processing basedon liquid displacement method. Themethod consists of immersing thesample in a glass container with anover flow spout. Water treated with asurfactant was used as thedisplacement liquid in the glasscontainer.

Weight loss or shrinkage ofmushrooms during canning is a majorproblem in the mushroom cannery. In

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Indian mushroom industry is stillpredominantly production and tradeof the fresh produce; processing too isrestricted to the preservation ratherthan the real value-addition. Almostentire domestic trade is in the freshform while all the export in thepreserved form (canned or steeped).Current era is characterized bygreater awareness about quality and,above all, with the demand for thereadymade or ready-to-make foodproducts. As mushrooms contain highmoisture and are delicate in texture,these can not be stored for more than24 hours at the ambient conditions ofthe tropics —weight loss, veil opening,browning, liquefaction and microbialspoilage often make the product totallyunsaleable. Effective processingtechniques will not only diminish thepostharvest losses but also result ingreater remuneration to the growersas well as processors. Value can beadded to the mushrooms at thevarious levels and to varied extent,right from grading to the readymadesnacks or the main-course item.Improved and attractive packaging isanother important but totallyneglected area in mushrooms- it isstill unprinted plain polypoucheswhereas attractive and labeled over-

wrapped trays are in vogue in thedeveloped countries. Real value-addedproduct in the Indian market is themushroom soup powder. Technologiesfor production of some other productslike mushroom based biscuits,nuggets, preserve, noodles, papad,candies and readymade mushroomcurry in retort pouches have beendeveloped but are yet to bepopularized. Attractive packaging ofthe value-added products is yetanother area which may be called thesecondary value-addition. While smallgrowers may add value by grading andpackaging, industry may go for theprocessed products for better returnsas well as improvement in the demandwhich shall have cascading positiveeffect on the production.

6.1. Mushroom soup powder

Soups are commonly used asappetizers but also as main course bythe diet-conscious. Experiments wereconducted to prepare good qualityready-to-make mushroom souppowder (Fig. 35 and Fig. 36) usingquality mushroom powder producedfrom the button mushroom and oystermushroom dried in the dehumidifyingair cabinet-drier.


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Fig. 35. Button mushroom soup powder

Fig. 36. Oyster mushroom soup powder

Dried button mushroom slices orwhole oyster mushrooms were finelyground in a pulveriser to pass through0.5 mm sieve. Mushroom soup powderis prepared by mixing this powder withmilk power, corn flour and otheringredients (Table 7). The detailedprocess flow chart (Fig. 37) for thepreparation of mushroom soup powderis given below.

This has to be mixed with equalquantity of water for the preparationof good quality mushroom soup withcharacteristic aroma and taste.

Singh (1996) developed a ready-to-reconstitute mushroom soup powderutilizing the vacuum concentratedwhey, a byproduct of dairy industry.

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Table 7. Ingredients for mushroom souppowder

Ingredients Parts(%)

Mushroom powder 16

Corn flour 5

Milk powder 50

Refined oil 4

Salt 10

Cumin powder 2

Black pepper 2

Sugar 10

Ajinomoto 2

Dried mushroom slices/ whole oyster�


Mushroom powder�

Addition of milk powder�

Addition of corn flour gelatinized inrefined oil @ 4 per cent

�Addition of ingredients

�Mushroom soup powder

Fig. 37. Flow chart for preparation ofmushroom soup powder

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6.2. Mushroom biscuit

Very delicious and crunchymushroom biscuits (Fig. 38) wereprepared at NRCM, Solan usingmushroom powder (both button andoyster) and ingredients viz., maida,sugar, oil, baking powder, ammoniumbicarbonate, salt, vanilla, milk powderand glucose. Fat in the form of oil isused in biscuits to remove hardnessand to improve the softness of thebiscuits – that is to lower the forcesnecessary to break and crush thebiscuits. The main sweetening agentis sugar and it also leads to enhancedcolour in the baked biscuit because ofthe Maillard reaction andpolymerization. Sugars also affect theheat denaturation of flour proteins.Ammonium carbonate is an aeratingagent and it has the advantage that itleaves no residue and evolves a greatervolume of gas per unit weight than anyof the other aerating agents but, in theabsence of phosphate and sodium ions,it leaves a new taste in the biscuits.

The various ingredients requiredfor the preparation of mushroombiscuits are listed in Table 8.

Fig. 38. Mushroom biscuits

The flow chart for mushroombiscuit preparation is presented belowas Figure 39. Sharma et al. (1991) alsosuccessfully prepared biscuits frommushrooms.

All the ingredients have to bemixed in a mixer for 3 to 5 min. The

R.D. Rai & T. Arumuganathan


Table 8. Ingredients for mushroom biscuits

Ingredients Parts(g)

Maida 100

Sugar 30

Fat 45

Baking powder 0.6

Ammonium bicarbonate 0.3

Salt 0.6

Vanilla essence 0.02

Milk powder 1.5

Glucose/Fructose 1.5

Water 12 to 22 %

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added to the prepared paste and roundballs of 2-4 cm dia are made out of thepaste. The prepared balls are spreadover a steel tray and are dried by sun-drying method and thus themushroom nuggets (Fig. 40) areprepared.

dough is kept at 300C in oven for 90min and then spread to a thickness of2 to 4 mm over a cleaned platform andcut into circular or rectangular shapes(required shape) and baked for 10-12min at 2100C in laboratory bakingoven.

6.3. Mushroom nuggets

‘Nuggets’ are generally preparedout of ‘pulse’ powder namely, Blackgram powder, Soybean powder, Uraddhal powder etc., and used in thepreparation of vegetable curry inNorth India. The nuggets add taste aswell as nutrients to the meal, since itis prepared from pulse powder. Forpreparation of mushroom nuggets,mushroom powder (dried and coarselyground mushrooms) is mixed with the‘Urad’ dhal powder and a paste isprepared by adding required quantityof water. Ingredients and spices are

Fig. 40. Mushroom nuggets

The ingredients used in thepreparation of nuggets at NRCM,Solan are listed in Table 9.

These nuggets can be relished intwo ways: straightaway this can bedeep-fried and used as snacks or canbe used in vegetable curry preparationalong with suitable vegetables or

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Table 9. Ingredients for mushroom nuggets

Ingredients Parts(%)

Mushroom powder 10

Urad dhal powder 80

Salt 2

Red chilly powder 1

Sodium bicarbonate 0.01

Water 7

Ingredients + Water�

Mixing (5 min)�

Keeping at 300C for 60-90 min coveredwith cloth



Oven drying at 2120C for 15 min�


Fig. 39. Flow chart for mushroom biscuits

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alone. Figure 41 shows flow chart forthe preparation of nuggets.

6.4. Mushroom ketch-up

Ketch-up is a common and popularproduct relished for its typical tasteand texture as accompaniment with

snacks. It is made by concentrating thejuice / pulp of the fruits / vegetableswithout seeds and pieces of skin, asthe skin and seed spoil the appearanceof the ketch-up. It does not flow freelyand is highly viscous in nature. Theyalso contain more of sugar and less ofacid.

Freshly harvested buttonmushrooms are washed, sliced andcooked in 50 per cent of water for 20min. Mushroom paste is preparedusing a mixer grinder. Arrarote (0.2per cent), acetic acid (1.5 per cent) andother ingredients (as given below) aremixed in the paste and cooked to bringits TSS to 350Brix. Then the ketch-upis filled in the sterilized bottles or jars.The various ingredients required forthe preparation of mushroom ketch-up are listed in Table 10.

Fig. 42. Mushroom ketch-up

R.D. Rai & T. Arumuganathan


Mushroom powder�

Mixing with dhal powder�

Making paste by adding water�

Mixing of ingredients and spices�

Making round balls of 2-4 cm dia�

Spreading on steel tray�

Sun drying�

Mushroom nuggets

Fig. 41. Flow chart for mushroom nuggets

Table 10. Ingredients for mushroomketch-up

Ingredients Parts(%)

Salt 10

Sugar 25

Acetic acid 1.5

Sodium benzoate 0.065

Onion 10

Garlic 0.5

Ginger 3

Cumin 1

Black pepper 0.1

Red chilly powder 1

Ajinomoto 0.2

Arrarote 0.2

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Joshi et al. (1991) developed sweetchutney from button mushroom andthe storage life of the product wasmore than a year.

6.5. Mushroom candy

A fruit or vegetable impregnatedand coated with sugar, subsequentlytaken out and dried is called a candiedfruit or vegetable. The process formaking candy is practically the sameas that employed in the case ofmushroom preserve describedelsewhere, with the difference that theproduce is impregnated with a higherconcentration of sugar. The total sugarcontent of the impregnated produce iskept at about 75 per cent to preventfermentation.

Fresh button mushrooms�



Cooking in 50 per cent of water for 20min�

Making of paste�

Addition of ingredients�

Cooking (350Brix)�

Filling in sterilized cans�

Mushroom ketch-up

Fig. 43. Flow chart for mushroomketch-up

Fresh mushrooms after harvestingare washed and halved longitudinallyinto two pieces. Halves are blanchedfor 5 min in 0.05 per cent of KMSsolution. After draining for half anhour these are treated with sugar.Sugar treatment is given at the rateof 1.5 kg sugar per kg of blanchedmushroom. Initially sugar has to bedivided into three equal parts. On thefirst day, blanched mushrooms arecovered with one part of sugar andkept for 24 h. Next day, the samemushrooms are covered with secondpart of sugar and are kept over nightand on the third day mushrooms areremoved from the sugar syrup. Thesugar syrup is boiled with 3rd part ofsugar and 0.1 per cent of citric acid tobring its concentration up to 70°Brix.Mushrooms are mixed with this syrupand again the contents are boiled for5 min to bring its concentration upto72°Brix. After cooling, the mushroomsare removed from the syrup anddrained for half an hour. The drainedmushrooms are placed on the sorting

Fig. 44. Button mushroom candy

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tables to separate, to reject defectiveand unwanted pieces. Finallymushroom pieces are subjected todrying in a cabinet dryer at 60°C forabout 10 h. As soon as these becomecrispy, all mushrooms are taken out,packed in polypropylene bags andsealed. The mushroom candy (Fig. 44)can be stored up to 8 months withexcellent acceptability and goodchewable taste.

The flow diagram for preparationof button mushroom candy is given asFigure 45.

6.6. Mushroom preserve(Murraba)

Murabba (preserve) is made frommatured fruit or vegetable, by cookingit whole or in the form of pieces inheavy sugar syrup, till it becomestender and transparent. In murabbapreparation, around 45 kg of fruit orvegetable is used for every 55 kg ofsugar and cooking is continued till a

Fig. 46. Mushroom murabba

R.D. Rai & T. Arumuganathan


Button mushroom�



Blanching in 0.05 per cent KMS for 5min.�

Sugar treatment @ 1.5 kg per kg ofblanched mushroom for 3 days

�1st day – covering blanched mushrooms

with 1st part of sugar for overnight�

2nd day-covering with 2nd part of sugar�

3rd day- removal of mushrooms from thesyrup�

Addition of remaining sugar + 0.1 % ofcitric acid to the syrup

�Boiling up to 700Brix.


Addition of mushroom pieces�

Boiling for 5 min to bring syrupconcentration to 720Brix.

�Cooling and removing of mushroom

pieces from syrup�


Drying at 600C for 10 h�

Packing and storage at cool and dry place

Fig. 45. Flow diagram for mushroom candy

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concentration of at least 68 per centof soluble solid is reached.

Fresh button mushrooms aregraded, washed, pricked and blanchedin 0.05 per cent KMS solution for 10

min. It is treated with 40 per cent ofits weight of sugar daily for 3 days.Then, mushrooms are taken out fromthe syrup and 0.1 per cent citric acidand remaining 40 per cent of sugar ismixed in the syrup. After bringing itsconcentration to 650Brix, mushroomsare added in the syrup and goodquality murabba (Fig. 46) is prepared.

The process flow chart forpreparation of mushroom murabba isgiven in Fig. 47.

6.7. Mushroom chips

The freshly harvested buttonmushrooms are washed, sliced (2 mm)and blanched in 2 per cent brine

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Fresh button mushroom�


Washing in 0.05 per cent KMS�



Adding 1 kg of blanched mushroom with400 g sugar and curing for 24 h

�Adding another 400 g sugar and curing for 24 h

�Removal of mushroom from syrup

�Add remaining 400 g of sugar and 0.1 per

cent citric acid�

Boiling upto 650Brix�

Addition of mushroom�

Boiling for 5 min�

Rapid cooling�

Packing in jars�

Mushroom murabba

Fig. 47. Flow chart for mushroommurabba (preserve)

Fresh button mushrooms�



Blanching in 2 per cent brine solution�

Dipping in solution of 0.1 % citric acid +1.5 % NaCl + 0.3 % red chilly powder

over night�

Drying in cabinet dryer at 600C for 8 h�


Spices spreading / mixing�

Ready-to-eat mushroom chips

Fig. 48. Flow chart for mushroom chips

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solution. The mushrooms are dippedovernight in a solution of 0.1 % ofcitric acid + 1.5 % of NaCl + 0.3 % ofred chilly powder. After draining offthe solution, the mushrooms aresubjected to drying in cabinet dryer at600C for 8 h. Then it is fried in therefined oil and good quality chips areprepared. The flow chart forpreparation of mushroom chips isgiven in Figure 48. Garam masala andother spices can be spread over thechips to enhance the taste. Afterspices mixing, the chips are packed inpolypropylene packets and sealed afterproper labeling.

6.8. Ready-to-serve mushroomcurry

In view of the growing market forthe readymade / ready-to-eat food itemsand keeping in mind the popularity ofthe Indian ‘Curry’ world over, atechnology was developed at NRCM,Solan for production of “Mushroomcurry in flexible-retortable pouches”by Chandrasekar et al. (2001). Flexibleretort pouch is an ideal alternate tometal containers for packing andstorage of heat processed foods.Flexible retort pouches, besides beingcheaper, have many other advantages

R.D. Rai & T. Arumuganathan


Table 11. Physical properties of the flexible retort pouch (laminate)

Thickness 105 µ

Polypropylene- outer layer 80 µAluminium- middle layer 12.5 µPolyester–outer Layer 12.5 µ

Tensile strength MD 451.5 kg/cm2

CD 425.4 kg/cm2

Elongation at Break MD 20 % CD 20 %

Heat seal strength MD 70.25 N / 25 mm width CD 60.75 N / 25 mm width

Bursting strength 2l psi

Bond strength of inner layer (Polyester) 184 g / 10 mm width

Bond strength of outer layer (Polypropylene) 110 g / 10 mm width

Pouch size 20 x 16 cm2

Weight 10 g

Seal size 10 mm

Lip size 4 mm

MD-along machine direction CD-along cross direction

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– easy bulk-packing and transport,sale and very convenient to the end-user. The retort pouch of 105 m thickwith polypropylene outer layer (80 m),aluminium middle layer (12.5 m) andpolyester inner layer (12.5 m)available in the market was used forpacking mushroom curry. Thephysical properties of the flexibleretort pouch (laminate) are given inTable 11.

The ingredients used to prepare thecurry are presented in the Table 12.In a frying pan, oil was added andheated. Sliced onions and greenchillies were added to the oil and friedtill golden brown. Garlic and gingerwere ground into a paste, added andlightly fried till oil reappeared. Currypowder, salt and red chilly powderwere added and lightly fried. Aboutone litre of water was added to thespices mixture and boiled till thickconsistency was obtained. Hundred

grams of cut mushrooms were filledin the retort pouch and 50 g of currywas added into the pouch. Then it washeat processed for FO value of 10 (final13.2) at 1210C for 43 min and cooledrapidly.

The ready-to-serve mushroomcurry (Fig. 49) prepared was deliciouswith good taste, attractive colour anda storage life of one year. Mushroomcurry was also successfully preparedfrom dried oyster mushroom andbutton mushroom after itsrehydration (Arumuganathan et al.,2004 b & c).

Fig. 49. Ready-to-serve mushroom curryin retort pouch pack (NRCM-Process)

6.9. Packaging materials formushroom products

Arumuganathan and Rai (2004)conducted studies to identify thesuitable packaging materials for themushroom products. The differentpackaging materials used were,polythene, polypropylene, lug bottles,laminated pouches, PVC wrapped

Post Harvest Technology of Mushrooms


Table 12. Ingredients for mushroom curry

Ingredients Quantity

Onion 510 g

Garlic 250 g

Ginger 200 g

Red Chilly powder 150 g

Curry powder 100 g

Green chilly 250 g

Oil 400 ml

Salt 160 g

Water 1000 ml

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trays, plastic jars and tin cans. Thesuitability and adoptability of thesepackaging materials were studied interms of keeping quality during the

storage period and are given in theTable 13. It is inferred that differentproducts required different type ofpackaging materials.

R.D. Rai & T. Arumuganathan


Table 13. Suitability of packaging materials for mushroom products

Name of the Mushroom Product StoragePeriodpackagingmaterial

Polythene bag Dried Mushroom 2 MonthsMushroom Powder 2 Months

Polypropylene Mushroom Candy 6 MonthsMushroom Soup Powder 6 MonthsMushroom Powder 6 MonthsDried Mushroom 3 MonthsMushroom Chips 3 Months

Lug bottles Mushroom Pickles 1 Year

PET jar Mushroom biscuits 3 monthsMushroom Candy 6 months

Butter Paper Mushroom Candy 3 monthsMushroom biscuits 2 months

PVC wrapped trays Mushroom Nuggets 1 month

Laminated pouches Mushroom curry 1 year

Tin Cans Canned Mushroom 1 year

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Among various preservationmethods, canning is the mostextensively used method for storageand trade of mushrooms. The processof sealing foodstuffs hermetically incontainers and sterilizing them byheat for long term storage is calledcanning or appertization. Canning isthe most popular method of preservingthe mushrooms for more than oneyear. Many Asian countries like India,China, Taiwan, Korea etc., exporttheir produce to the American andEuropean Countries in the form ofcanned mushrooms. Infrastructurefor a canning unit is described here.It may be mentioned that this canningunit can be used for canning anyproduce and the capacity of most ofthe machine is one ton mushroom per

shift of 8 hours (3 tons per day).However, bigger, automated, importedand FDA approved canning units areestablished in 100 % EOU bigmushroom commercial units in India(Fig. 50).

7.1. Lid-Embossing machine

This machine (Fig. 51) is used toemboss the lids with the requiredreference letter or figures like date ofmanufacture, date of expiry, rate,batch number, brand name andquantity. This machine is operated bya foot treadle which, when depressed,embosses the lid by virtue of markerdies, without piercing it.

Fig. 50. Imported automatic canningunit

Fig. 51. Lid embossing machine


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7.2. Can reformer

This is simple machine (Fig. 52),which makes the flattened can bodiesto round, prior to flanging. Theflattened can is mounted on to therubber roller and on depressing thepedal, it presses the can against therotating steel roller there by giving ita round shape. The capacity of the canreformer varies from 600 to 800 cansper hour.

for simultaneous flanging of both sidesof the round can obtained from can-reformer. A toggle motion balancedhand-lever enables the machine to beoperated with minimum exertion.

7.4. Flange rectifier

This is a simple hand operatedmachine (Fig. 54) used forrectification of misshaped flanges ofcans. The misshaped flanged can isplaced on the die and by simpleapplication of the handle the flange isrectified.

Fig. 52. Can reformer

7.3. Can flanger

This simple hand operatedmachine, shown in Figure 53, is used

Fig. 53. Can flanger

Fig. 54. Flange rectifier

7.5. Steam jacketed kettle

This machine (Fig. 55) is mountedon a heavy duty mild steel stand withtilting arrangement. The pan has adouble jacket for maximum steamutilization and efficiency. Both the panand jacket are made up of high qualitystainless steel. This is mainly used forbatch heating and blanching ofmushrooms in brine solution. Thecapacity of the steam jacketed kettle

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is 100 Gallons. It is also available inthe smaller capacity of 25 and 50Gallons.

7.6. Exhaust box

This machine (Fig. 56) consists ofa chain conveyor moving at low rpmto keep the cans filled withmushrooms to contact with steam for1 to 2 min to get it sterilized. It canpass two A-2½ size cans at a time andthe over all length of the exhaust boxvaries from 14, 16 and 18 feet.

7.7. Double-seamer

This is a semi-automatic machine(Fig. 57), most suitable for seamingprocessed cans as well as flanged canswith the embossed lids on both sides.The capacity of the double seamingmachine is approximately 600 cans perhour and heavy-duty double seamersalso available at the capacity of about2000 cans per hour.

Fig. 55. Steam jacketed kettle

Fig. 56. Exhaust box

Fig. 57. Double-seamer

7.8. Canning retort

This equipment (Fig. 58) is usedfor sterilization of cans underpressure, after filling and seaming. Itis equipped with pressure gauge andsafety valve. The capacity of thecanning retort is 280 to 300 cans of A-2½ size and it is also available in thesmaller capacities like 21, 75-80, 90-100 cans of A-2½ size

7.9. Layout of canning unit

A general layout of a canning unitof about 200 TPA is given here.

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the national and global market, whichwould be most advantageous.

7.9.2. Canning unit site

While selecting the site for thefactory, the following points should beconsidered.

a. Desired quantities of the type ofmushrooms should be readilyavailable at reasonable price in thelocality, because mushrooms arehighly perishable and deterioratein long distance transport.

b. Proper transport facilities shouldexist for the movement of rawmaterials and finished products.

c. The factory environment shouldbe clean and free from pollutionand garbage etc. If the factory isto be located in an industrial area,the site should be at a considerabledistance from other industrialfactories spreading smoke anddisagreeable odours, which mayadversely affect the quality of thecanned product. There should alsobe facilities for disposal of thecannery wastes.

d. There should be scope for futureorderly expansion of the factory.

7.9.3. Cannery buildings

The building may be single-storeyed or multi-storeyed. Where theplant is a comparatively small one and

However, minor modifications can bedone according to availability of landand capital. Canning unit or anyprocessing unit should not be less 100m2 area as per FPO. Beforeestablishing a commercial canningunit, it is necessary to consider certainimportant factors such as investment,factory site, factory building, watersupply, labour etc., in addition to FPOlicense from the Ministry of FoodProcessing. A typical layout of acanning unit is given in the Figure 59.

7.9.1. Investment

The capital outlay for canning unitincludes investment on land, factorybuilding and machinery. The runningor operational expenses include thecost of raw material, labour,processing, storage, transport anddistribution. The entrepreneur shouldplan the type and size of productionaccording to the existing demand in

Fig. 58. Canning retort

R.D. Rai & T. Arumuganathan


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Store(12’ x 13’)

Office(12’ x 12’)

Boiler8’ x 8’



A- Grading table B- Washing tanks C- Steam jacketted kettlesD- Cooling & Steving (grading) E- Can filling table F- Can flangerG- Brine tank H- Exhaust box I- Double seamerJ- Retorts K- Cooling tank L- Lid embossing machineM- Chain pulley N- Can Rectifier R- Can Reformer






Fig. 59. Lay-out of a canning unit

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works for short periods during theyear, a single storeyed building of lightconstruction will do. In case of thelarger plants, that have to run almostthroughout the year, multi-storeyedconstruction is desirable as it wouldfacilitate and cheapen the movementof raw as well as finished products.For 200 TPA unit, single storybuilding with processing area of notless than 100 m2 with separate roomfor boiler, store room for empty canand filled cans will be sufficient.

Flooring should be firm and of goodcement to withstand the constant useof water and the movement of heavy-wheeled machines. A slope of about 5.5cm per metre is necessary for properdrainage. All doors, windows andventilators should be provided withfine wire mesh to prevent entry of fliesand other insects. The roof of thebuilding should be high and wellventilated to provided outlet forvapours and steam. The windowsshould have large glass panes, andpart of the roof should be of groundglass to permit gentle light inside.There should be provision for efficientartificial lighting as the cannery willhave to work at night quite often.

A sufficient number of dressingand toilet rooms should be providedseparately for men and womenworkers in the factory premises. Theworkers should be taught theimportance of personal hygiene.

7.9.4. Water supply and drainage

Large quantities of water arerequired for cleaning mushrooms,making brine, washing floors andmachinery etc. so there should beabundant supply of potable water. Thewater system should work atsufficiently high pressure so thatsupplies can be made at differentpoints in the cannery without a break.The water should not be alkaline orvery hard, and should be free fromorganic matter. Presence of iron andsulphur compounds renders itunsuitable for making brines. Saltishwater should be avoided, as it wouldaffect the taste of the products. Ifsupplies of the desired quality are notavailable, it would be necessary toinstall a water-softening plant.Further, the boiler feed water requiresion-exchange treatment to bring it tothe desired pH and make it free fromscale-forming ions.

7.9.5. Labour and hygiene

All the workers in the factory,whether employed on regular basis orrecruited during rush periods, shouldwear clean cloths and aprons to ensurehygienic conditions. They should beexamined medically at regularintervals as a precaution againstinfectious diseases. An efficient systemof chemical and microbiologicalcontrol at various stages of themanufacturing process (HACCP)should be maintained to avoid the risk

R.D. Rai & T. Arumuganathan


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of contamination and foodpositioning. There should be a foodtechnologist to supervise the work andto ensure desired standard ofproduction. A clean factory operatedwith strict observance of thefundamental principles of sanitationis mandatory for the production ofcanned mushrooms of high quality.

7.9.6. Machinery and equipments

Great attention is required in theselection of machinery and otherequipments. Different types of unitsare in use, but the entrepreneur hasto determine his own requirements.

Efforts should be made to buy thewhole unit from one supplier. Thewhole equipment should be arrangedin a proper order so that minimumtime and effort are needed for handlingthe products at all stages ofmanufacture. In short, the rawproduct should move practically in astraight line till it emerges as thefinished product, ready for labelingand packing. During the off-season theentire machinery should beoverhauled, greased and painted. Apackage of machinery required for 200TPA mushroom canning is givenbelow:

Post Harvest Technology of Mushrooms


S.No. Name of the machine Unit Cost (Rs)

1. Can reforming unit of 600/800 cans per h capacity with 1 60,000flanging dies with rings and rubber mandral with shaft& Cone

2. Double seaming machine of 600 cans/h capacity with 1 55,000seaming chucks & seaming rollers

3. Lid embossing machine with 2 row 6 digits die 1 20,000

4. Flange rectifier 1 10,000

5. Steam jacketed double wall kettle (100 gallons) 2 2,00,000

6. Exhaust box (16 ft / 18 ft) 1 80,000

7. Canning retort with two crates (300 cans A 2½) 2 90,000

8. Stainless steel working table (3' x 8') 2 30,000

10. Hand refractometer 1 1,500

11. Seam checking gauge 1 500

12. Can tester 1 3,000

13. Vacuum tester 1 1,000

14. Aluminum trays for handling of cans 4 4,000

15. Boiler with necessary fittings and accessories 1 1,00,000

Total 6,55,000

Unforeseen expenditure @ 5 % 32,750

Total cost of canning unit excluding cost of land and building 6,87,750

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S.No. Particulars Rs. in Lakhs

1. Land 500 sq. meter 5.00

Total Rs. 5.00


S.No. Particulars Area Unit cost Total (Lakhs)

1. Boundary wall 90 M 1500/RMT 1.35

2. Canning room (50’ x 25’) 1250 ft2 750/ft2 9.38

3. Boiler room (8’ x8’) 64 ft2 750/ft2 0.48

4. Road (inner) - - 1.00



S.No. Raw materials Quantity Rate Amount

1. Cans (A1 size) 5,00,000 Rs. 5/can 25,00,000

2. Cans (A2½ size) 2,50,000 Rs. 10/can 25,00,000

3. Mushroom 330 tons Rs. 40/ton 1,32,00,000(1.65 tons/ton of final product)(30 tons for 200 tons final product)

4. Chemicals, lables and - - 3,00,000miscellaneous items


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Post Harvest Technology of Mushrooms



S.No. Cost Rs. in Lakhs

1. Raw materials 185.00

2. Salaries and wages 3.00

3. Power and fuel 2.00

4. Overheads 2.00

5. Depreciation (10% on building and 15% on machinery) 2.27

6. Interest on term loan (15% of 25.00 lakhs) 3.75

7. Interest on the working capital (18% of 6.00 lakhs) 1.80

Total cost 199.10 lakhs

Sales of 5,00,000 cans of A1 size at Rs. 25.00 125.00 lakhs

Sales of 2,50,000 cans of A2½ size at Rs. 50.00 125.00 lakhs

Total sales 250.00 lakhs

Profit 50.90 lakhs


S.No. Particulars Rs. in Lakhs

1. Land 5.00

2. Buildings 12.21

3. Plant and Machinery 7.00

4. Contingencies 2.00

5. Pre-operative expenses 2.00

6. Margin money for the working capital 2.00

Total 30.21

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9.1. Preparation of pickle

Pickling of mushroom is already ahouse-hold to commercial venture.Mushroom growers do preparemushroom pickle of the market-surplus and also from the open anddefective mushrooms. Smallentrepreneurs buy mushrooms fromthe growers and make mushroompickle. However, major production ofmushroom pickle comes from theCanneries doing mushroom canning.In fact, canning rejects, which is about10 % of the raw material, areconverted into mushroom pickle thussaving an avoidable loss in thecanning of mushrooms; cost of suchpickle is also low.

Freshly harvested mushrooms aresorted based on their size and the

graded mushrooms are washedthoroughly in clean water to removethe adhering casing soil and foreignmatter on the surface (Fig. 60) and theexcess water is drained off. Thecleaned mushrooms are halved byusing a sharp, clean stainless steelknife (Fig. 61) and the halvedmushrooms are subjected to blanchingimmediately by dipping them in aboiling solution of 0.05 per cent KMS+ 0.1 per cent of citric acid and 2 %brine for 10 min. Blanching is done toinhibit enzymatic activity and toinactivate microorganisms. Theblanched mushrooms are subjected tosalt curing process in which 10 percent sodium chloride is added and keptovernight. The excess water oozed outof mushrooms is removed on the nextday and appropriate preservatives aremixed to get organolepticallyacceptable mushroom pickle.

Fig. 60. Washing of button mushroom Fig. 61. Slicing of button mushroomsfor pickle preparation


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9.2. Preservatives and spices

The following preservatives andspices are used to prepare tasty buttonmushroom pickle.

1) Acetic acid (@ 1-1.25 %)2) Sodium benzoate (@ 650 ppm)3) Salt (@ 9-10 %)4) Rai (Black mustard) powder (@

3 %)5) Turmeric powder (@ 2 %)6) Redchilli powder (@ 1.5 %)7) Cumin powder (@ 1 %)8) Black pepper powder (@ 1 %)9) Aniseed powder (@ 1 %)10) Fenugreek seed powder (@ 1 %)

11) Kalonji (@ 1 %)12) Ajwain (@ 1 %)13) Mustard oil (@ 20 %)

Acetic acid and sodium benzoateare mixed with the salt treatedmushroom pieces. All the spices exceptajwain and kalonji are mixed in groundform and added to that. Finally ajwainand kalonji as a whole are fried for 2-3min in mustard oil and mixed with themushroom slices. At the end, mustardoil is poured and mixed into pickle. Theprepared mushroom pickle can bestored upto one year.

The cost of preparation for thebutton mushroom pickle is workedout as outlined in the Table 14.

Post Harvest Technology of Mushrooms


Table 14. Cost of preparation for the button mushroom pickle

S. N0. Ingredient Quantity Rate/kg Cost (Rs*)

1. Button Mushroom 175 g 40.00 7.002. Salt 15.75 g 7.00 0.1103. Acetic acid 1.7 ml 40.00 0.0684. Sodium benzoate 0.1225 g 50.00 0.0065. Rai powder 5.25 g 60.00 0.3156. Turmeric powder 3.50 g 100.00 0.3507. Red chilli powder 2.625 g 120.00 0.3158. Cumin powder 1.7 g 150.00 0.2559. Fenugreek powder 1.7 g 60.00 0.10210. Aniseed powder 1.7 g 100.00 0.17011. Kalonji 1.7 g 60.00 0.10212. Ajwain 1.7 g 100.00 0.17013. Oil 26.5 ml 50.00 1.325

Fuel 1.00Labour charges 3.00NET MUSHROOM PICKLE 238.95 g 14.288

Cost of preparation for 1kg button mushroom pickle = Rs.60.00* Cost at Solan Market

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Boilers and blowers

1. Lal Sons & Company,1663/1, Mukerjee Marg,New Delhi - 110 006.

2. Indcon Boilers,D-9/6, Okhla Industrial Area,Phase-I, New Delhi - 110 020.Ph: 011-26815336Fax:

3. Indvent Engineers Pvt. Ltd.,C-12, Amar Colony Market,Lajpat Nagar, New Delhi - 110 024.

4. Laxmi Boilers (North),602, Deepali, 92, Nehru Place,New Delhi - 110 019.

5. Thermax Ltd.,9, Community Centre, Basant Lok,New Delhi - 110 057.Ph: 011-46087200Fax:

6. Urjex Industries,S-26, Industrial Estate,Partapur, Meerut - 250 102.Telefax: 0121-2440597

7. Lalsons & Company,A-45, Mayapuri Industrial Area,Phase-I, New Delhi - 110 064.Ph: 011-25138121Fax: 011-25147483

Cabinet drier

1. Widsons Scientific Works,10, Sadar Thana Road, Sadar BazarDelhi - 110 006.Ph: 011-23537765

Canning machinery and cans

1. Mather and Platt (India) Ltd.,805-806, Ansal Bhawan,16, Kasturba Gandhi Marg,New Delhi - 110 001.Ph: 011-3712840

2. M/s B. Sen Barry & Company,65/11, New Rohtak Road,Karol Bagh, New Delhi - 110 005.Ph: 011-25723553

3. M/s Bajaj Machines,21, Kantinagar, PO Krishna Nagar,Delhi - 110 051.

4. Divecha Glass Industries,249, Bal Rajeshwar Road,185, Marg Mulund (W),Mumbai - 400 080.


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5. K.S.T. Foods and Services Pvt.Ltd.,C-07/87, Vishnu Prasad MahantRoad,Vile Park, Mumbai - 400 057.

6. M/s Techno Equipments,31, Parekh Street,Mumbai - 400 004.

7. Rollatainers Ltd.,13/6, Mathura Road,Faridabad - 121 003.Ph: 0129-2271709Fax:

8. The Tin Plate Co. of India Ltd.,4, Bankshall Street,Kolkata - 700 001.Ph: 033-22435401Fax:

9. Poysha Industrial Co. Ltd.,Tiecicon House,Dr. E.Moses Road,Mumbai – 400 011.Ph: 022-4964378Fax: 022-4964379

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