FRUIT PROCESSING

7/30/2019 FRUIT PROCESSING

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EXPLORING FRUITS AND VEGETABLES PROCESSING TECHNOLOGY

THAT IS PROFITABLE AND COMPATIBLE TO SMALL SCALE

PROCESSORS

Compiled By:

D.K. ENGINEERING CO.LTD

MARCH 2005


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TABLE OF CONTENTSTABLE OF CONTENTS ..................................................................................................................................................... 2

1.0 INTRODUCTION .......................................................................................................................................................... 3

1.1 Background ................................................................................................................................................................. 3

1.2.1 Production ................................................................................................................................................................ 3

1.2.2 Processing ................................................................................................................................................................ 4

1.3 Statement of the Problem ............. ............. .............. ............. ............ .............. ............. ............ .............. ............. ............. 4

1.4 Justification of the Study ................................................................................................................................................ 51.5 Goals and Objectives ...................................................................................................................................................... 6

1.5.1 Goals ........................................................................................................................................................................ 6

1.5.2 Objectives ................................................................................................................................................................ 6

1.6.0 Literature Review ........................................................................................................................................................ 6

1.6.1 Previous Studies on Processing of fruits and vegetables ......................................................................................... 6

1.6.1.1 Processing Technology ..................................................................................................................................... 7

1.6.1.2 Processing Skills ............................................................................................................................................... 7

1.6.1.3. Quality Control Services ............ .............. ............. ............ .............. ............. ............ .............. .............. ............ 7

1.6.1.4 Raw Material Supply ........................................................................................................................................ 8

1.6.1.5 Infrastructure .................................................................................................................................................... 8

1.6.1.6 Marketing of Processed Products...................................................................................................................... 8

1.6.1.7 Capital............................................................................................................................................................... 9

1.6.2 Fruits and Vegetables as raw Materials for Processing ............................................................................................... 9

1.6.2.1 Fruits ..................................................................................................................................................................... 91.6.2.1.1 Harvesting, Collection and Storage of Fruits ............................................................................................... 11

1.6.2.2 Vegetables .......................................................................................................................................................... 12

1.6.2.2.1 Harvesting and Pre-processing Considerations .............. ............ .............. ............. ............ .............. ............. 12

1.7.0 Methodology .............................................................................................................................................................. 14

1.8.0 Results and Discussion .............................................................................................................................................. 14

1.8.1 Small-Scale Processing of Fruits and Vegetables .................................................................................................. 14

1.8.1.1 Selection and Procurement of Raw materials ................................................................................................. 14

1.8.1.2 Preliminary Unit Operations ........................................................................................................................... 15

1.8.1.3. Processing of Fruit Juices ...................................................................................................................................... 17

1.8.2 Equipment Layout ..................................................................................................................................................... 22

1.8.3 Equipment required and Their Sources....................................................................... Error! Bookmark not defined.

1.8.4 Identification of Packaging Materials ......................................................................... Error! Bookmark not defined.

1.8.3.1 Packaging Material for Fruit Juices .................................................................................................................... 23

1.8.3.2 Packaging Materials for Dried Fruits and Vegetables ........................................................................................ 231.8.5 Detailed Recipes for Processing of some Fruits and Vegetables Products ................................................................ 24

1.8.5.1 Processing of Mango Nectar ............................................................................................................................... 24

1.8.5.2 Processing of Orange Juice ................................................................................................................................. 25

1.8.5.3 Processing of Mango Bars .................................................................................................................................. 26

1.8.5.4 Processing of Mango Slices ................................................................................................................................ 27

1.8.5.5 Processing of Dried Cabbages/Kales .................................................................................................................. 28

1.8.5.6 Processing of Dried Carrots ................................................................................................................................ 29

1.8.5.7 Processing of mango Jam ................................................................................................................................... 30

1.9.0 Conclusions and Recommendations .......................................................................................................................... 31

1.9.1 Conclusions ........................................................................................................................................................... 31

1.9.2 recommendations ................................................................................................................................................... 31

2.0 References .................................................................................................................................................................... 32

List of Figures

Fig.1: Flow diagram for small scale juice processing ............. .............. ............ .............. ............. ............ .............. ............. 19

Fig.2: Flow diagram for small scale processing of Dried Fruits ............ .............. ............. .............. ............ .............. .......... 20

Fig.3: Flow diagram for Small- scale Processing of Dried Vegetables21


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EXPLORING FRUITS AND VEGETABLES PROCESSING TECHNOLOGY THAT IS

PROFITABLE AND COMPATIBLE TO SMALL SCALE PROCESSORS

1.0 INTRODUCTION

1.1 Background

Kenya has a land area of 583,000Km2 with an estimated population of 32 million people.

About 83% of the land is either arid or semi- arid, leaving only 17% for high and medium

potential farming. The high and medium potential areas are characterised by high

population pressure, small land sizes and competition for the limited land resource for

planting of such farming practices as coffee, tea, dairy, fruits and vegetable farming as well

as planting of food crops. This has led to settlement and farming activities in the arid and

semi arid lands (ASALS) that are characterised by high poverty levels, inadequate water

supply for irrigation and livestock production activities. Most of the ASALS lie within the

Eastern and Coast Provinces. Horticulture is one of the main commercial activities in the

provinces, consisting mainly fruits and vegetables farming. Production of vegetables is

however limited to the few areas where irrigation water is available.

1.2 Production and Processing of fruits and vegetable

1.2.1 ProductionThe horticultural sub-sector, which comprises fruits, vegetables and flowers, has continued

to grow, despite the overall decline in economic growth. In 2003, the sector earned 36.49

billion in foreign exchange. The total hecterage under horticulture in 2003 was estimated at

2,456,191 hectares. Despite the good performance, there are various problems facing the

sub-sector namely:

Competition of Kenyan exports from other horticultural exporters

Poor infra-structure, especially roads, leading to high post-harvest losses

Low yields obtained by many small scale farmers

Limited access to new crop varieties, market demand and timely market information

Wrong use of pesticides

Inadequate water supply for production and processing

Delays in sea freighting of produce and

Poor financing and high interest rates on loans.


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1.2.2 Processing

Fruits and vegetables are highly perishable. Consequently, about 70% of these products go

to waste either on farm or during transportation to the market. This underscores the need to

process them in order to make them shelf stable. Although there are some large companies

that have ventured into this field there are some constraints that hinder development of

viable enterprises based on fruits and vegetables, especially by the small scale processors

which include:

Acquisitions of raw materials - most fruits and vegetables have a seasonal glut i.e. the

maturity and harvest season is only a short time during a certain period of the year. This

makes the supply to fluctuate between under-supply, unavailability, poor quality and

over-supply.

Lack of technical expertise to process fruits and vegetable most of the small scale

fruits and vegetables enterprises are started by local entrepreneurs who have capital but

little or no technical skills in food processing. Most of them are not trained Food

technologists.

Presence of product substitutes, especially squashes based on sugars and synthetic

colours and flavours. These are much cheaper than fruit based beverages but are of no

nutritional value to the consumer.

Lack of processing machinery and equipment - most of the small-scale enterprises

utilise kitchen utensils such as blenders and sieves to make their products. Theoperations of these entrepreneurs are cottage type and normally carried out in

residential houses, making them less likely to meet the stipulated hygienic and quality

standards for these products. This directly affects the marketability of these products.

1.3 Statement of the Problem

Coast has emerged to be a fruit surplus area. The government of Kenya through the

ministry of Agriculture initially spearheaded the production of the fruits and vegetable.

Provision of high quality seeds by the ministry of agriculture led to increase in yields. The

targeted peasant farmers who constitute 75% of the population in the province have

perfected the farming techniques, increasing the yield to the extent that the immediate

market is unable to absorb the produce. However, the poverty level has remained well


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above 70%, giving indication that little has been achieved in terms of wealth creation and

poverty alleviation to the people.

When the fruits and vegetables are in season, there are increased losses through spoilage

and exploitation by middlemen who pay as little as 30 cents per orange. There is only one

processor who makes Picana juice. The farmers are not able to venture into the market on

their own due to well-defined cartels that are not ready to pay the right price for the fruits.

On the other hand, the processor offers very low and unprofitable prices during the season

due to over-supply. After the season the period of scarcity sets in.

Currently, there is little knowledge on fruits and vegetable processing for the small-scale

entrepreneur. The technology available is pulping with a blender and refrigerating which

can extend the shelf life of the juice to a maximum of three days. The situation is made

worse by inaccessibility to proper, hygienic and food grade packaging by small-scale

processors. As for the vegetables, the produce is overwhelmingly high during the rainy

season while there is almost nothing when the season is over and the vegetables have to

be imported from upcountry.

1.4 Justification of the Study

Training for enterprise development (TED) sets out to bridge the gap by developing small-

scale technology that is affordable and easy to use in order to open up the sub-sector to

small enterprises. This is expected to increase the value of the farm produce as well as the

profitability to the farmers. Further, the results obtained will pave the way to implementation

of small-scale fruits and vegetables processing technology by other communities.


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1.5 Goals and Objectives

1.5.1 Goals

To create employment through spawning of viable fruit and vegetable enterprises.

To provide access to the market by the fruit and vegetable farmers.

To contribute to the national food security measures

To introduce new and viable products to the local market

To provide access to the fruits and vegetables processing technology by the small-

scale entrepreneurs.

To create lessons that will be widely shared in the country.

1.5.2 Objectives

To define and specify the stages in the small-scale fruit and vegetable processing,

including procurement, processing through to packaging as well as the equipment that is

used.

To develop a set of equipment that will give the final quality processed products,

including fruit juices, fruit purees and concentrates, dried fruits and vegetables as well

as other products that may appear viable for small scale production.

To identify the right and acceptable food grade packaging materials available locally

To price and cost the process in order to determine the competitiveness of the final

product in the market.

1.6.0 Literature Review

1.6.1 Previous Studies on Processing of fruits and vegetables

A number of studies on the processing of fruits and vegetables have previously been

carried out. The following is a summery of the issues raised in the reports reviewed:


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1.6.1.1 Processing Technology

Various studies carried out have revealed lack of processing technology, especially for the

small-scale enterprises. A study carried out by Kenya Industrial Research and Development

Institute (KIRDI) on Metal Based Agro-Processing Technology For Development Of Micro

And Small Enterprises In Kenya in 1998 established that all the enterprises investigated

used technology adapted from larger firms. The study, however, observed that the mode of

adaptation involved making the technology quite rudimentary as a result of omission of vital

processing stages during adaptation, thereby compromising quality of the final product. A

study undertaken by ILO/FIT Project in 1994 emphasises the need to have locally

fabricated fruit processing equipment such as pulpers, pulp finishers and presses and back

up service for imported equipment. Another study by Mungai et al, 2000, noted that

individual small scale processors do not fully package and adopt technology for processing

but tend to leave vital stages, resulting with inferior products.

1.6.1.2 Processing Skills

The literature reviewed indicated that most of the entrepreneurs lacked necessary skills to

run their enterprises. The study by KIRDI (KIRDI, 1998) found that some of the

entrepreneurs did not have any clue as to where to get the information while others thoughtthat one has to pay a very high fee to get such information. Mungai et al, 2000 highlights

barriers to entry into, processing as lack of information on domestic market, quality

standards and technological factors.

1.6.1.3. Quality Control Services

Lack of quality control services or any quality assurance system has been identified as a

major factor in inhibiting the growth of small-scale fruit and vegetable processing

enterprises due to inconsistencies in product quality and hence limited marketability of the

same.


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1.6.1.4 Raw Material Supply

The seasonality of the agricultural raw materials makes it difficult for the processors to

operate all year round, especially if one is dealing with one type of fruit or vegetable. They

are also unable to operate at full capacity and this reduces profitability of their enterprises.Regular supply of raw material is also a problem because most of the small-scale

processors do not enter into contractual agreements with the suppliers of their raw

materials and this makes the deals rather unreliable.

1.6.1.5 Infrastructure

Poor infrastructure is a major hindrance to the growth of small scale processing of fruits and

vegetables. The studies undertaken reveal that some of the enterprises are located in areas

that where there is no electricity and this rules out the possibility of using electricmachinery. Poor road network in some of the areas where the enterprises are located

hinders easy movement of raw materials and processed products, thereby inhibiting growth

of the enterprise.

1.6.1.6 Marketing of Processed Products

Small-scale processors face a problem of locating a market for their products. This is due to

a combination of factors namely:

Inability to transport their products beyond the regions where they process them makes

them compete for the limited market around the area where they process them.

Competition from fruit flavoured drinks - the cost of raw materials and processing is

high, making the prices of the products much higher than those of the substitutes and

hence less affordable to majority of consumers.

Lack of consumer awareness on the use of processed fruits and vegetables as a result

of limited research and promotion of these products.

For those who may wish to process for export, the high raw material, machinery and

processing costs as well as high freight charges make the prices for the products

uncompetitive in the international market.


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1.6.1.7 Capital

Most of the small-scale processors lack funds to buy the necessary machinery and they do

not have access to credit facilities. Interest rates on loans are also high and discourages

borrowing by the small scale processors.

1.6.2 Fruits and Vegetables as raw Materials for Processing

1.6.2.1 Fruits

Fruits are edible products of plants, consisting of seeds and envelope especially when the

latter is juicy, fleshy and sweet and they are eaten essentially as desert items.

Composition of fruits varies with the botanical variety, cultivation practices and weather

conditions. It also changes with the degree of maturity before harvest and condition of

ripeness, which is progressive after harvest and influenced, by storage conditions.

In general, however, most fresh fruits are high in water, low in protein and low in fat. In most

cases, the water content is greater than 80%. Commonly, protein content is less than 3.5

and fat content less than 0.5% (except for avocado and olive, which contain 20% and 15%

fat respectively).

Fruits are important sources of indigestible as well as digestible carbohydrates. The

digestible carbohydrates are present as sugars (e.g. glucose and fructose) and starches

while the indigestible ones consist of cellulosic materials used as roughage in the body.

Fruits are also important sources of minerals and certain vitamins, especially vitamin A and

C. Precursors of vitamin A e.g. -carotene are found in yellow to orange fruits such as

oranges and pawpaws. Citrus fruits are excellent sources of vitamin C. Examples of citrus

fruits are oranges, tangerines and lemons.


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Table 1: Vitamin C Content of Some Fruits

Fruit Vitamin C content(mg/100g

Apple 2 10

Avocado 7 10Banana 10 - 30Guava 300Lemon 50Melon 25 30Orange 50Tangerine 30

Plum 3Pear 4Pineapple 25

Strawberry 60

Tomato 25Passion fruit 25

Fruits also contain organic acids which contribute to:

i. Colour changes due to the presence of some compounds called anthocyanins, which

change colour with changes in pH.

ii. Taste the sugar acid ratio (i.e. sugar % / acid %) determines the taste of the fruit.

Sugar gives the sweetness, while the acid gives the sourness. During ripening, sugar

increases while acid decreases. The balance between sugar % and acid % gives the

final taste of the fruit. Harvesting has to be done at the best sugar:acid ratio.

iii. Preservation fruits owe their preservative effects on organic acids. Microorganisms

do not grow under very low pH of less than 4.6. Most fruits have pH below this value.

Only fungi can survive in such pH and are therefore the main spoilage agents in fruits.

Pigments in fruits give them the different colours while volatile compounds give them their

characteristic flavour (aroma and taste). Among the pigments is the chlorophyll giving the

green colour and the carotenoids responsible for the yellow orange colours in the fruits.

Volatile compounds include esters, alcohols, acids and carbonyl compounds (aldehydes

and ketones).


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1.6.2.1.1 Harvesting, Collection and Storage of Fruits

Fruits continue living even after harvesting. There is therefore continued respiration, giving

off carbon dioxide, moisture and heat. These products of respiration have to be considered

when choosing materials for storage, packaging and refrigeration of fruits.

Changes in composition of fruits take place before and after harvest and during ripening

and storage. These include changes in carbohydrates, pectins and organic acids. These

changes influence the quality attributes of the fruit.

The quality of fruits or products processed from them is influenced greatly by the degree of

maturity and ripeness when the fruit is picked and the method of picking or harvesting.

There is a difference between maturity and ripeness of a fruit. Maturity is the conditionwhen the fruit is ready to eat or if picked will become ready to eat on further ripening.

Ripening is that optimum condition when colour, flavour and texture have developed to their

peak. Some fruits are picked when they are mature but not yet ripe mainly because of their

soft nature when ripe which renders them vulnerable to mechanical damage and also, since

many fruits continue to ripen off the tree, they are picked before peak ripeness to avoid

over-ripening before processing. The proper time to harvest fruits depends on variety,

location of the farm with respect to market, weather and ease of removal from the tree,

which changes with time.

After picking, the fruits require to be handled with care to avoid mechanical injuries. Crates

bearing some cushioning material may be used for transportation. Since the fruits are still

respiring, releasing moisture and heat, the material used has to be permeable to moisture

and some kind of cooling has to be provided, especially if the fruits are being held in the

container for a long period.

If the fruits are not to be processed immediately, they have to be stored under the right

conditions of temperature and relative humidity to avoid spoilage. Different fruits have

different optimum refrigeration temperatures and these should be used if cold storage is to

be employed. Accumulation of moisture in the storage room should be avoided by allowing

free flow of air in the room.


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Table 2: Refrigeration Temperatures for Some fruits

Fruit Optimum Temperature (oC) Storage Period at optimumTemperature (Weeks)

Banana (ripe) 10 2Banana (green) 10 1-2

Mango 5-9 2-3Avocado 5-9 3-5

Passion fruit 5-9 3-5

Pineapple-Ripe

-Unripe5-910

4-54-5

Plum -1-4 2-7Orange 5-9 6-12Lemon 10 12-20Pear -1-4 8-30

Apple -1-4 8-30

1.6.2.2 Vegetables

Vegetables are derived from various parts of the plant. Different vegetables are associated

with the parts of the plant they represent since this provides clues to some of the

characteristics expected in them. Vegetables are classified as earth vegetables (roots,

modified stems, corms, tubers, modified bud), herbage vegetables (leaves, petioles, flower

buds, sprouts, shoots) and fruit vegetables (legumes, cereals, vine fruits, berry fruits, tree

fruits).

1.6.2.2.1 Harvesting and Pre-processing Considerations

Vegetables undergo continuous changes as they grow and mature in the field. In due cause

they reach peak quality in terms of colour, texture and flavour. This peak quality is quick in

passing and may last only a day. Harvesting should be scheduled strictly to capture this

peak quality.

Vegetables continue to live after harvest and may quickly pass the peak quality as a result

of physiological changes taking place in them. The physiological changes lead to alteration

of chemical composition of the vegetable as some constituents are changed from one form

to another e.g. conversion of sugars to starch in sweet corn. This affects the vegetables


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sweetness and freshness of flavour. Some sugars are also lost through respiration while in

some vegetables like asparagus, some of the sugars are converted to fibrous tissue,

leading to a more woody texture.

Another concern during transportation and storage of vegetables is evolution of heat

through respiration. The heat leads to deterioration of vegetables and speeds up growth of

microorganisms. This necessitates cooling of the vegetables if they are not processed

immediately after harvest. Care must be taken, however, to ensure that the optimum cold

storage temperature for each specific vegetable is used to store the vegetable because

some vegetables, e.g. cucumber, deteriorate when stored under too low temperatures

conditions.


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1.7.0 Methodology

The study involved the following tasks

Review of available literature and documentation on small-scale fruits and vegetable

processing.

Identification of the necessary processing machinery for small-scale fruits and vegetable

processing and sources of such equipment. This involved visiting various fabricators of

processing machinery in order to locate where the required machinery could be

purchased.

Processing of various fruits and vegetables products using recipes obtained from

literature to establish their applicability and suitability and making necessary

modifications where necessary, including stabilisation and improvement of texture and

other quality attributes of the products. This lead to development of detailed processflows for processing of given fruits and vegetables as well as the layout for the

processing equipment.

Determination of shelf stability of the products using accelerated shelf life determination

tests.

Identification of the appropriate packaging materials for the processed products and

their sources. This entailed assessment of characteristics of different packaging

materials with respect to their suitability for packaging of various processed fruit and

vegetable products.

1.8.0 Results and Discussion

1.8.1 Small-Scale Processing of Fruits and Vegetables

1.8.1.1 Selection and Procurement of Raw materials

Selection of raw materials is a very important step in the processing of fruits and vegetables

because the quality of the processed product is greatly influenced by the quality of the raw

materials used. Although selection will depend on the type of product to be made, the

material selected should be of sound condition and good overall quality.

Procurement of the raw materials may be done through various ways depending on location

of the enterprise with respect to the source of raw material. The processor may have his/her


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own farm and process the materials near the farm in which case there is no problem of

transporting the material to the processing site or s/he may purchase the material from a

wholesale market and transport them to the processing site. On the other hand, the

processor may rely on middlemen to deliver the raw materials to the processing area. In

this case the processor has a responsibility of making sure the middlemen understand the

rules governing harvesting and transportation of fruits and vegetables to avoid their

deterioration as detailed under section 1.6.2. The processor must himself/herself be very

conversant with these rules. The processor can also get his/her materials through contract

purchasing whereby s/he contracts a farmer to plant the materials for him/her as s/he

supplies the farm inputs. This way, he/she may be in a position to have control over the

quality of the raw materials purchased.

1.8.1.2 Preliminary Unit Operations

Before actual processing, fruits and vegetables go through preliminary treatments to render

them more suitable for processing. These include sorting, grading, washing, removal of

unwanted parts, peeling, size reduction (slicing, dicing etc) and blanching. The specific unit

operations applied will depend on the raw material and the type of product being made.

i) Sorting

This involves removal of rotten, mouldy, damaged, unripe or over-ripe fruits and all

extraneous mater such as leaves and stalks, from the raw materials.

ii) Grading

This is done to get the material of the required quality. The material may be graded for

colour, appearance, size and shape. For example, the fruits used for making mango slices

may need to be of a uniform size and shape to give slices of uniform size and shape,

thereby ensuring uniform rate of drying. On the other hand, size and shape is not an

important factor in fruits for juice making. All these can be done visually in a small scale

processing unit but determination of size and shape in large establishments is usually

mechanised.


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iii. Washing

This involves use of water and food grade detergents to remove physical dirt (e.g. soil),

microorganisms and pesticide residues.

iv. Removal of unwanted Parts

This includes removal of cores, pods, calyx, peels, eyes, stones and damaged parts. The

main functions here include:

(a) Peeling: -Most fruits are peeled before processing. It involves removal of peel or cover.

This may be done through various methods:

Hand peeling by use of stainless steel knives.

Abrasive Peeling a rough container is used. The material is put in the container,

which is then shaken to bring the material into contact with the rough surface. Water

is then sprayed onto the container to remove the skins. It is best suited for round

shaped material such as oranges.

Hot water peeling the material is dipped in hot water to loosen the skin. Gentle

rubbing then removes the skins. It is applied in plums, tomatoes and citrus fruits.

(b) Trimming: - This involves removal of unwanted parts after peeling e.g. ends of fruits

such as pears.

(c) Pitting or destoning - This is the removal of pits/stones in fruits like plums and

mangoes.

(d) Coring-Removal ofcentre core in fruits like pineapple and pears.

v. Cutting (slicing, dicing etc): - This is intended to reduce the size of the material. Thematerial may be cut into slices, halves, dices, rings, shreds, grates, chips etc.

vi. Blanching: - This is a short heat treatment given to raw materials prior to processing,

with the main aim of inactivating enzymes. It may be done with use of hot water or

steam. Heat blanching is more common with vegetable than fruits because in the

latter, it leads to turgor loss from heat damage, sogginess and juice drainage after

thawing of frozen fruits. In fruits chemicals are used to inactivate oxidative enzymes orto act as antioxidants. Chemicals used include:

Sulphur Dioxide: - this is used to control enzymatic reactions that lead to discolouration

of fruits and vegetables, especially during and after peeling. It also inactivates

microorganisms, thereby preventing microbial spoilage of the materials. Solutions of

0.25% SO2 or its equivalent in form of solutions of sodium sulphite, sodium


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metabisulphite are used. Fruits should be dipped in the solution for about one minute

and then removed so as not to absorb too much So2, which has an unpleasant taste and

odour. The materials are then allowed to stand for about two hours to allow penetration

of SO2

Ascorbic Acid (Vitamin C) Dip: - This used to prevent oxidation, which may lead to

discolouration of the fruits. It is dissolved in sugar syrup. Levels of 0.05 to 0.5% Ascorbic

acid are used.

Sugar syrup: - This minimises oxidation by coating the fruit, thereby preventing contact

with atmospheric oxygen. Sugar syrup also prevents loss of volatile flavours and adds to

the sweetness of the fruits

These chemicals are used to prevent enzymatic oxidation that causes darkening of colour

and alteration of flavour in fruits intended for freezing and drying.

The actual processing unit operations applied after the above preparatory treatments

depend on the type of product being made.

1.8.1.3. Processing of Fruit Juices

Juices are beverages derived from fruits and are used for quenching thirst. Preparation of

juices varies depending on the type of fruit and the product being made. However, thepreliminary treatments listed above apply to all the fruits. General steps for processing of

juices include:

1. Selections of raw materials Completely ripe fruits are used. Size and shape is not

important in the selection of raw material for juices.

2. Size reduction of the material - this involves maceration, comminution or crushing of the

fruits to destroy the cellular structure of the fruits. Crushers, hammer mills etc. can be

used. This applies to such fruits as pineapples and pears but44 not to others like

oranges and passion fruits.

3. Juice extraction from the material this may be done by passing the material through a

finisher. It separates the material into juice, seeds, pulp and peels if peeling had not

been done. The thickness of the pulp is controlled by use of different screens as

required. The process removes the undesirable material.


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4. Clarification some juices such as orange juice and apple juice have to be clarified

using fine sieves or cloth to get rid of solid substances.

5. Pasteurization different juices are given different heat treatments but generally

temperatures of 70-90oC are used.

6. Packaging The juice is aseptically packaged hot in clean sterile containers.

Alternatively, the juice could be packaged and then pasteurized afterwards.


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Fig.1: Flow diagram for small scale juice processing

Harvesting of fruits

Reception

Sorting and Inspection

Washing

Trimming/coring/pitting/size

reduction

Juice extraction

Clarification/Homogenization

Pasteurization

Packaging

Storage/sale

Pasteurization

Packaging

Pasteurization

70-80oC

Pasteurization

Cooling

Ambient temperature

Packaging


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Fig.2: Flow diagram for small scale processing of Dried Fruits

Harvesting of fruits

Reception

Sorting and Inspection

Washing

Peeling/Trimming/coring/pitting

etc

Slicing/pulping

Sulphiting with sodium

sulphite solution)

Drying

Packaging

Storage/sale


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Fig.3: Flow diagram for Small- scale Processing of Dried Vegetables

Harvesting of vegetables

Reception

Sorting to (remove

defective) and Inspection

Washing

Peeling/Trimming (for some

vegetables)

Slicing/dicing/shredding

Blanching and sulphiting in

boiling water for a few

minutes.

Drying

Packaging

Storage/sale


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1.8.2 Equipment Layout

Reception and

sorting area

Washing

troughs

Pulper Homogeni

zer/mixer

Manual

filling

PasteurizerCooling

troughs

Packing table

StoreDispatch

Supervisors

desk


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1.8.3.1 Packaging Material for Fruit Juices

The material that was found suitable for packaging of the fruit juices was glass bottles

because these can resist the high temperatures required for Pasteurization/sterilization

of the juices after filling or hot filling of pasteurized juice.

1.8.3.2 Packaging Materials for Dried Fruits and Vegetables

The materials that were found suitable for the packaging of dried fruits and vegetables

are glass/polyethylene Tetraphthalate (PET) jars or laminated/metalized polyethylene

sachets because these materials good barrier properties against water vapour

(moisture) and oxygen which is an important requirement for dried fruits and

vegetables.


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1.8.5 Detailed Recipes for Processing of some Fruits and VegetablesProducts

1.8.5.1 Processing of Mango Nectar

Ingredients

Ripe, good quality mangoes

Lemons 2 spoons per kg of pulp

Sugar 200g/kg of pulp

Boiled water 1 litre/kg of pulp

Procedure

Select completely ripe good quality mangoes

Sort out any unripe, rotten, mouldy, insect damaged or diseased mangoes

Wash the mangoes in clean water with food grade detergent

Peel the mangoes with stainless steel knives.

Remove the stone as you cut the mangoes into smaller pieces

Extract the juice from the fruit using the manual extractor

Add boiled water, sugar and lemon juice. The final mixture should have 12% solids

and a pH of 3.5 3.8. Citric acid may be used to adjust acidity instead of lemon

juice.

Homogenize the juice using a manual mixer to get smooth, uniform texture.

Fill the juice into bottles and place then in the metallic holder. Sterilize in boiling water for 30 minutes.

Transfer the boiling water to a cooling basin and fill the remaining space with cold

water. Leave the bottles there for about 10 minutes and transfer to a basin of cold

water then leave them to cool to ambient temperature.


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Remove from cooling basin and place them on the packing table and leave them to

drip-dry.

Label the bottles with a label bearing the following information:

Name of the product

Name and contact address of the manufacturer

Date of manufacture

Expiry date

Batch number

Nutritional information.

Pack into crates and take to the store to await sale.

1.8.5.2 Processing of Orange Juice

Ingredients

Fully ripe, good quality oranges

Sugar

Procedure

Select completely ripe good quality oranges

Sort out any unripe, rotten, mouldy, insect damaged or diseased oranges.

Wash the oranges in clean water with food grade detergent and then rinse

thoroughly with clean water.

Peel the oranges with stainless steel knives, making sure the inner spongy layer is

completely removed.

Extract the juice from the fruit using the manual extractor. Care should be taken not

to over-squeeze the oranges because this may lead to the juice becoming bitter. The


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albedo (white spongy layer or mesocarp), rag (pith and membranes), pulp and

seeds produce bitter juice if the orange is excessively squeezed.

Filter the juice with a fine sieve or cloth to ensure all the solid particles are

removed.

Add sugar at the rate of 5-10% of the weight of the juice.

Fill the juice into glass bottles and close.

Sterilize them by boiling in water for 1minute

Cool, allow them to dry and then label them.

Keep them in the store to await sale.

1.8.5.3 Processing of Mango Bars

Ingredients

Fully ripe good quality mangoes

Sugar 10% of the weight of the pulp

Lemon juice 2 spoons per kg of pulp

Sodium metabisulphite 2g pr kg of pulp

Procedure

Select completely ripe good quality mangoes

Sort out any unripe, rotten, mouldy, insect damaged or diseased mangoes

Wash the mangoes in clean water with food grade detergent and then rinse



Remove the stone by chopping off the flesh and cutting it into smaller pieces

Extract the pulp with the manual extractor


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Add sugar, lemon juice and Sodium metabisulphite. The mixture should contain

25% soluble solids as determined by a refractometer.

Heat the pulp at 70-80oC for 2 minutes

Pour the pulp into Alluminium trays coated with glycerine at the rate of 15kg/m

2

Glycerine prevents the pulp from sticking on the tray and facilitates removal of the

product after drying.

Place the trays in the solar drier and leave to dry until the product has 15%

moisture and a leather-like structure. The drying period depends on the weather

conditions.

Remove the product from the trays and cut it into small blocks of about 4x4x1 cm

Each block is wrapped in sheet of metalized polyethylene. A number of bars can

then be packed together in an appropriate secondary package such as a glass or

plastic jar.

Keep in the store to await sale.

1.8.5.4 Processing of Mango Slices

Ingredients

Half ripe mangoes without fibres

Boiled water 1liter

Sugar 700-800g/litre of water

Sodium metabisulphite 3g/liter of water

Lemon juice 2 spoons per litre of water

Procedure

Select half ripe good quality mangoes

Sort out any rotten, mouldy, insect damaged or diseased mangoes

Wash the mangoes in clean water with food grade detergent and then rinse



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Slice the into 6-8 mm thick slices with a stainless steel knife.

Soak for 18 hours in a solution containing boiled water, sugar, lemon juice and

sodium metabisulphite according to the quantities given above. Drain off the solution and place the slices on perforated aluminium trays

Place the trays in the solar drier and leave to dry until they attain a moisture content

of 15%

Package the slices in glass/plastic jars or metalized polyethylene poaches.

Pack the jars or poaches in carton boxes and keep in the store to await sale.

1.8.5.5 Processing of Dried Cabbages/Kales

Ingredients

Good quality cabbages/kales

Boiling water

Salt 50g/litre of water

Sodium metabisulphite 50g/litre of water

Procedure

Select good quality cabbages or kales

Sort out the diseased or insect infested leaves from the kales.

Remove the outer leaves from cabbages.

Remove the cores and cut the cabbages/kales into 5mm strips.

Wash them to get rid of dust, soil and any remaining insects.

The vegetables/kales are placed in a perforated container and dipped for 3 minutes

in boiling water containing salt and Sodium metabisulphite according to the

quantities given above.


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The product is then evenly spread on perforated trays of a drier until a moisture

content of 5% is attained.

Package in metallized polyethylene poaches and pack in carton boxes, taking care

not to pack them too tightly to avoid crushing them.

Keep in the store to await sale.

1.8.5.6 Processing of Dried Carrots

Ingredients

Good quality carrots

Boiling water

Salt 50g/litre of water

Sodium metabisulphite 3g/litre of water

Procedure

Select good quality carrots with uniform diameter

Sort out rotten or insect damaged carrots

Remove the stalks and tips.

Wash the carrots in clean water.

Scrape or peel them and cut into slices of about 5mm thickness.

Dip, for 3 minutes, in boiling water containing salt and Sodium metabisulphite

according to the quantities given above.

Spread evenly on perforated aluminium trays and leave to dry until 6% moisture

content is attained.

Package in metalized polyethylene pouches, pack in carton boxes and keep in the

store to await sale.


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1.8.5.7 Processing of mango Jam

IngredientsRipe/half ripe mangoes

Sugar 55% of the wait of the puree

Procedure

Sort out the defective fruits

Wash the fruits with food grade detergent and rinse thoroughly with clean water.

Peel the fruits with a stainless steel knife.

Remove the stone by slicing off the flesh

Pass the mango pieces through a pulping machine

Add 75% of the sugar and adjust pH 3.3

Boil the mixture for 25 to 30 minutes.

Add the rest of the sugar 5 minutes before the end of process (the temperature of

the product should be 101-105oC at the end of the process*).

Cool to about 70oC and hot fill the product in sterile containers.

Cool the product to 38oC using clean potable water

Pack the containers in carton boxes and keep in store to await sale.

*The end of process (when the material is ready to set) can be determined through the

following methods:

By determination of the total solids which should be 65 oBrix.

Determination of the temperature which should be 101-105oC.

Putting a drop of the material on a cool surface and leaving it to set.

Dropping a cold drop of the material into cold water in a glass; the drop should

settle as a mass; if it spreads on the top, the material is not ready for setting.


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1.9.0 Conclusions and Recommendations

1.9.1 Conclusions

It has been possible to define the stages in small-scale fruit and vegetable processing

as well as the equipment used and their sources. Food grade packaging materials for

the products have also been identified. More information is required for pricing and

costing to be done.

1.9.2 recommendations

The project is a worthwhile venture and should be implemented immediately.


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2.0 References

Potter, N. N.,1987. Food Science Third Edition.

ILO/FIT, K-MAP, 1984. Preliminary Analysis of the Fruit Processing Sub-Sector in Kenya

Mungai, J.K., Ouko, J. and Heiden, M., 2000. Processing of Fruits and Vegetables

In Kenya

KIRDI, 1998. Study Assignment on Metal Based Agro-Processing Technologies.

FAO, Rural Processing and Preserving Techniques for Fruits and Vegetables

Internet: http://www.upasitearesearch.or/std_content.html

FRUIT PROCESSING

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