EffectofMicrowaveCookingonQualityofRiceberryRice...

Research ArticleEffect of Microwave Cooking on Quality of Riceberry Rice(Oryza sativa L)

Lyda Chin Nantawan Therdthai and Wannasawat Ratphitagsanti

Department of Product Development Faculty of Agro-Industry Kasetsart University Bangkok 10900 ailand

Correspondence should be addressed to Nantawan erdthai faginwtkuacth

Received 9 October 2019 Revised 8 August 2020 Accepted 13 August 2020 Published 28 August 2020

Academic Editor Marıa B Perez-Gago

Copyright copy 2020 Lyda Chin et al is is an open access article distributed under the Creative Commons Attribution Licensewhich permits unrestricted use distribution and reproduction in any medium provided the original work is properly cited

Microwaves have been applied for cooking warming and thawing food for many years Microwave heating differs fromconventional heating andmay cause variation in the food qualityis study determined the quality of Riceberry rice (Oryza sativaL) after microwave cooking using various rice-to-water ratios at three power levels (360 600 and 900W) e texture of allmicrowave-cooked samples was in the range 16235plusmn 586 to 18011plusmn 717N and was comparable to the conventionally cookedrice (16203N) e total phenolic content (TPC) and the antioxidant activity of the microwave-cooked rice were higher thanthose of the conventional-cooked rice Microwave cooking appeared to keep the TPC in the range 24115ndash24689mg GAE100 gdb and the antioxidant activities based on DPPH and ABTS assays in the ranges 13424ndash13715 and 30280ndash31185mgmiddotTE100 g dbrespectively Microwave cooking also maintained similar contents of fiber ash and total starch to those from conventionalcooking e glycemic index (GI) for all freshly cooked rice samples was not significantly different and the rice was classified as ahigh-GI food Microwave cooking could be recommended as an alternative technique for rice cooking due to its rapid heatingregime and the comparable quality and maximized TPC and antioxidant activity of the cooked rice

1 Introduction

Rice (Oryza sativa L) is a vital staple food that is grown inmany countries including ailand which is known as oneof the highest rice producers ai rice has a great variety ofcolors ranging from black or dark purple to ruby red goldenbrown and white Regular consumption of some varietiescontaining high antioxidant activities can benefit humanhealth Riceberry rice is a new crossbreed between Jao HomNin rice and Jasmine rice 105 It is a pigmented rice whichhas a deep purple whole grain with a unique aroma Re-cently Riceberry rice has become popular for local con-sumption due to its unique cooked grain characteristics suchas fluffy texture flavor nutritional value and health-pro-moting effects such as anti-inflammatory anticancerhyperlipidemic and hypoglycemic [1 2] Due to its health-enhancing substances Riceberry rice has gained attentionfrom researchers and food manufacturers as a waste product(Riceberry bran) and as flour and whole grain It has beenused for developing new natural and healthy food and

commercial food products as well as in dietary supplementscosmetics and pharmaceuticals [3 4]

To cook grains into a palatable pleasant and digestibleform rice needs to be boiled or steamed to accomplishsuitable starch gelatinization and water absorption Sincepeople in different countries have different preferences thecooking methods vary resulting in two primary cookingtechniques e first involves cooking in large amounts ofwater with subsequent drainage commonly referred to theexcess or the American method while the other is based oncooking the rinsed rice in a measured amount of watercommonly known as the Pilaf or the oriental method or thewater-absorption method [5] Europeans mostly prefer tocook rice in excess water while Asians typically use a ricecooker with a limited amount of water

Tamura et al [6] mentioned that eating quality was notonly affected by grain characteristics inherent in differentcultivars but was also related to cooking procedures such asthe rice-to-water ratio and the cooking temperature Overtime many heating appliances have evolved including three-

HindawiJournal of Food QualityVolume 2020 Article ID 4350274 9 pageshttpsdoiorg10115520204350274

stone fires electric cookers microwave ovens inductioncookers and other high-tech appliances Shinde et al [7]reported 10ndash25 variation in the operation efficiency ofconventional cooking Currently more emphasis is placedon energy conservation being environmental friendly andon hygienic production thus microwave heating has be-come more attractive than traditional heating Microwavesare known to generate heat inside the penetrated mediumbecause of the induced molecular friction in an alternatingelectromagnetic field e increased interest in microwavingfoods has been encouraged by its faster heating featureslower energy consumption convenience and maintenanceof nutritional integrity [8] e Ca K Mg P and Zncontents of jalo and black bean species increased after do-mestic microwave cooking while the contents of Cu Fe andS did not change [9] e antioxidant activity of somevegetables such as Momordica charantia and Moringaoleifera could be also enhanced by microwave heating [10]Microwaves are mostly used for drying blanching andpasteurization in food industries e catering industry usesmicrowave ovens mainly for reheating preprepared products[11] Recently traditional thermal processing has beenreplaced by microwave cooking due to the accelerated paceassociated with the modern lifestyle

Conventional cooking using an electric cooker involvesheating as a combination of conduction (between the heaterand the bottom of the container) convection (between theliquid phase and the container) and convection (betweenthe water and rice grains) In contrast microwave cookinggenerated heat by dipolar rotations and ionic interactions[5 12 13] ese different heating mechanisms could affectthe quality of the cooked food For example the firmnessand chewiness of steamed nonglutinous rice were higherthan those from boiling in an electric cooker Interestinglythe anthocyanins in pigmented rice decreased by around80 after cooking in an electric cooker whereas the phenoliccompounds declined by 54 [4] Ayimbila and Keawsom-pong [1] demonstrated that the slow digestion of the starchin Riceberry rice was accelerated depending on the cookingmethod e differences in the starch fractions were at-tributed to the processing conditions and variation in theamount of water which played a crucial role in starch ge-latinization and retrogradation mechanisms during cookingand storage Besides the hydrolysate of Riceberry rice sig-nificantly enhanced the growth of probiotic strains during invitro fermentation

Chatthongpisut et al [14] reported that the degradationpathway of anthocyanins under microwave heating wasdifferent from conventional heating resulting in differentdegraded products Although extremely high-temperaturetreatment promoted the degradation of anthocyanins inaipurple rice it generated phenolic compounds such asprotocatechuic acid (PCA) vanillic acid and ferulic that hadan antiproliferative effect on Caco-2 cells After cooking theconcentration of PCA significantly increased approximately121ndash3 times compared with the raw rice Yamuangmornet al [4] reported that the antioxidant capacity of cookedpurple nonglutinous rice contrasted in its anthocyaninconcentration indicating that there could be a higher

concentration of other antioxidant compounds after cook-ing For this reason cooking Riceberry rice using micro-waves could result in different profiles of anthocyaninsphenolic compounds and biological activity compared withusing an electric cooker

erefore this study aimed to evaluate possible alter-native cooking methods for Riceberry rice in a domesticmicrowave oven and the effect of microwave cooking onantioxidant activities and qualities e study outcomeswould facilitate decisions on cooking rice to maximize itsnutrient content for everyday consumption

2 Materials and Methods

21 Materials and Chemical Reagents e Riceberry riceused was a commercial product purchased from a localmarket in ailand and stored in a cool room until use Adomestic microwave oven with a frequency of 2450MHz(MP-94825S LG Electronics Inc Korea) and an electriccooker (Model Sharp KSH-D06 Federal Electric Corp Ltdailand) were used for this study

All chemical reagents consisting of gallic acidFolinndashCiocalteu reagent 22-diphenyl-1-picrylhydrazyl(DPPH) 6-hydroxy-2578-tetramethylchromane-2-car-boxylic acid (Trolox) 22-azino-bis-3 ethylbenzothiazoline-6-sulphonic acid diammonium salt (ABTS) methanol andethanol were of analytical grade and purchased from Sigma-Aldrich (St Louis MO USA)

22 Sample Preparation and Rice Cooking Cooked rice wasprepared in three steps namely washing cooking andwarming A classical cooking procedure for rice was chosenfor the preliminary study Rice grains were washed threetimes (1min each time) to eliminate all dirt on the grainsTwo different cooking methods were used microwavecooking using a domestic microwave oven and conventionalcooking using an electric cooker When the cooker auto-matically shifted to the warm setting the rice was held for10min at that setting according to the cooker manualwhereas the rice was allowed to stand for 5min after mi-crowave cooking

e experiment used a completely randomized designere were nine treatments involving either conventionalcooking or microwave cooking For conventional cooking100 g of Riceberry rice grains were prepared in a cookerRice-to-water ratios of 1 18 1 20 and 1 22 (w v) werepreliminarily determined to obtain the optimal quality withcooking times of 32min 34min and 37min respectivelyand designated as EC1 EC2 and EC3 respectively Formicrowave cooking 50 g of rice was placed in a microwaverice-steaming container (Model Sistema 26 L New Zealand)with a limited water ratio en the rice-steaming containerwas placed on the center of the turntable plate in the mi-crowave chamber and heated using three power levels(360W 600W and 900W) Rice-to-water ratios of 1 28(L-MC1) and 1 30 (L-MC2) were used for microwavecooking at 360W At 600W the rice-to-water ratio was

2 Journal of Food Quality

increased to two levels of 1 48 (M-MC1) and 1 50 (M-MC2) With the maximum power at 900W the rice-to-water ratio was further increased to 1 70 (H-MC1) and 1 72 (H-MC2) e variation in the rice-to-water ratio ap-plied was to balance evaporation loss during cooking ecooking time for each condition was varied to yield palatablecooked rice (Table 1) Rice samples were confirmed to becompletely cooked if there was no white core in the ricegrains when compressed between two glass plates ecooked rice was immediately freeze-dried Freeze-driedsamples were ground and kept at minus18degC for chemicalanalysis e physical quality was analyzed in the freshlycooked form

23 Determination of Cooking Profiles and Texture of CookedRice

231 Determination of Temperature Profile and WaterUptake during Cooking e temperature profile and wateruptake during cooking were observed every 2min until therice was cooked e rice and water temperature wasmeasured using a K-type thermocouple device connected toa data logger (Digicon DP-72 Digital ermometer ai-land) e water uptake was determined by checking theweight of the rice [15] e weight of the rice before cooking(W1) was recorded Twenty samples were prepared andcooked individually for different times to obtain palatableeating quality (Table 1) After cooking each rice sample wasleft for 30 s on a filter paper to remove surface water beforebeing reweighed (W2) e water uptake ratio was calculatedusing the following equation

water uptake ratio W2

W1 (1)

Experiments for determination of both the temperatureprofile and water uptake were carried out based on tworeplications

232 Determination of Texture Profiles of Cooked Ricee texture of the cooked rice was analyzed using a textureanalyzer (Model TA XT plus Stable Micro Systems UK)following the method by Wu et al [16] with some modi-fications Twenty cooked rice grains were arrayed on theplatform and tested for 5min after cooking had finished Atwo-cycle compression program (TPA) was run with speedsof 05 05 and 5mms for the pretest test and posttestrespectively A cylindrical probe (P75) was used to achieve60 compressione experiment was repeated 10 times foreach sample e textural parameters of TPA curves werecalculated using the Texture Expert Excede Version 10software (Stable Micro System Software UK)

24 Comparison of Chemical Qualities from ConventionalCooking and Microwave Cooking

241 Determination of Total Phenolic Content and Anti-oxidant Activities Free phenolic compounds were extracted

using the method by Wiriyawattana et al [2] A groundsample was homogenized in 85 (vv) methanol with a ratioof 1 10 wv under shaking at room temperature for 30minAfter centrifugation (Model Rotina 380R Hettich Tut-tlingen Germany) at 3000 rpm for 10min the supernatantwas decanted e precipitate was re-extracted e super-natant samples collected from three extractions werecombined and made up using a solvent (methanol 85 vv)to the final volume of 50mL e extract was used to de-termine the total phenolic content (TPC) and antioxidantactivities using the DPPH radical scavenging assay and theABTS radical scavenging assay Extractions were conductedin duplicate

e amount of TPC was determined using theFolinndashCiocalteu colorimetric method e extract (200 microL)was mixed with 15mL of sodium carbonate (75 gL) and15mL of the FolinndashCiocalteu solution (1 10 vv)emixedsolution was incubated in the dark at a room temperature for2 he absorbance was read using a UV-spectrophotometer(Model 160A Shimadzu Japan) at 725 nm Gallic acid wasused as a standard e results were expressed as milligramsof the gallic acid equivalent per 100 g of the dry sample (mgGAE100 gmiddotdb)

For the DPPH radical scavenging activity assay theextract (500 microL) was added with 3mL of 01mM DPPHmethanol solution e solution was kept at room tem-perature for 30min before the absorbance was measured at517 nm using the UV-spectrophotometere DPPH radicalscavenging activity was calibrated based on a standard curveof Trolox and expressed as milligrams of the Troloxequivalent per 100 g of the dry sample (mg TE100 g db)

e ABTS radical scavenging activity was determinedaccording to Chatthongpisut et al [14] with some modifi-cations A sample of the extract (100 microL) was mixed with39mL of the working solution e absorbance was mea-sured at 734 nm immediately after keeping in the dark for6min e results were expressed as milligram of the Troloxequivalent per 100 grams of the dry sample (mg TE100 gmiddotdb)

242 Proximate Analysis e content of crude protein fatfiber moisture and ash in cooked rice samples was deter-mined according to the Association of Official AnalyticalChemists (AOAC) standard methods e carbohydratecontent was calculated by subtracting the moisture proteinfat fiber and ash contents of cooked rice from 100 [17] Allanalyses were conducted in triplicate ese results wereexpressed on a dry weight basis

243 Total Starch and Estimated Glycemic Index e totalstarch content of each sample was determined using a totalstarch assay kit (Megazyme International Ireland LtdIreland) e released glucose was measured as the absor-bance of the coloration using the UV-spectrophotometer at510 nm Total starch () was expressed on a dry weight basis[18]

Starch digestion was determined using a rapid in vitrodigestibility assay based on glucometry [19] e glucose

Journal of Food Quality 3

concentration in the digesta was measured using a bloodglucometer (Model Easymax Hsinchu Science Park Tai-wan) after a specific time (0 10 20 30 45 60 90 120 150180 210 and 240min) Digested starch (DS) per 100 g drystarch was calculated using the following equation

DS 09 times GG times 180 times VW times S [100 minus M]

(2)

where GG is the glucometer reading (mML) V is thevolume of the digesta (mL) 180 is the molecular weight ofglucose W is the weight of the sample (g) S is the starchcontent of the sample (g100 g sample) and 09 is thestoichiometric constant for starch from glucose contents

e hydrolysis index of each sample was calculated bydividing the area under its digestogram by the area under thedigestogram of white bread Single-point measurement ofstarch digestion at 90min (HI90) in the samples was alsoused to calculate the glycemic index (GI) Hence using theparameter of the modified first-order kinetic model for boththe rice sample and white bread (reference) the average GI(GIavg) for each sample was calculated using the followingequation [18]

GIavg 3921 + 0803HI90( 1113857 +(3951 + 0573HI)( 1113857

21113890 1113891

(3)

where HI90 is hydrolysis at t 90min and HI is hydrolysis att 120min

25 Statistical Analysis Data were analyzed using one-wayanalysis of variance in the SPSS version 120 for Windowssoftware (SPSS Inc Chicago IL USA) Duncanrsquos test wasused to determine significant differences among means(Ple 005)

3 Results and Discussion

31 Effect of Rice-to-Water Ratio and Cooking Method onCooked Rice Quality With the range of rice-to-water ratiosused in conventional cooking the rice grains required10min to reach the maximum temperature of 9785degCcompared to only 6min using microwave cooking

(Figure 1) e rate constant (k-value) of the temperatureincrease was significantly different between the cookingmethods However the rice-to-water ratio did not have asignificant effect on the temperature increase during con-ventional cooking Likewise under the same microwavepower increasing the rice-to-water ratio did not affect therate constant (Pgt 005) e k-value decreased from1467degCmiddotminminus1 to 1351degCmiddotminminus1 when the microwave powerdecreased from 900W to 360W Although the rate constantat high and low power varied the difference was muchsmaller than those between microwave cooking and con-ventional cooking probably due to the variation in heatingmodes In the current study the results indicated that highmicrowave power required a greater water content forcooking than low microwave power due to the increasedevaporation at high power Water is a dipolar molecule thatcan absorb microwave energy and transform it into heat dueto its polar interaction During the heating process the vaporpressure is increased contributing greatly to vapor loss fromthe system [13 20] Gavahian et al [12] reported that thehigher evaporation rate from microwave cooking led to agreater rate of temperature increase than from the tradi-tional method

In the water uptake profiles (Figure 2) the cookingmethod had a significant effect on the rate constant exceptfor EC3 (k 0033minminus1) and L-MC1 (k 0035minminus1)iswas possibly due to the slight variations in the rice-to-waterratio (from 22 to 28) and heating power (300W from theelectric cooker and 360W from the microwave oven)However the rapid water uptake with microwave cooking atmedium and high power could have been related to theinitial water content and the cooking temperature becausestarch begins to gelatinize only when the water content in therice grain is above the critical water content [21]

With microwave cooking an increase in the rice-to-water ratio did not significantly affect the rate constant ofwater uptake e hydration rates increased after increasingthe microwave power from low to medium and high levelsindicating that medium and high power resulted in rapidhydration of the rice grains is was supported by thetemperature profile results (Figure 1) e temperatureincreases for the medium and high power levels were sig-nificantly higher than for the low power level Likewise He

Table 1 Experimental conditions for rice cooking

Cooking method Power level (W) Rice-to-water ratio (w v) Cooking time (min)EC1 mdash 1 18 32EC2 mdash 1 20 34EC3 mdash 1 22 37L-MC1 360 1 28 30L-MC2 360 1 30 315M-MC1 600 1 48 30M-MC2 600 1 50 31H-MC1 900 1 70 30H-MC2 900 1 72 305EC conventional cooking using an electric rice cooker L-MC microwave cooking using low power level M-MC microwave cooking using medium powerlevel and H-MC microwave cooking using high power level 1 low water ratio 2 medium water ratio and 3 high water ratio


et al [22] mentioned that water absorption in cooked ricewas influenced by the cooking temperature e amount ofwater uptake by starch granules increased at high temper-ature due to the effects of the crystalline structure of thegranules the breaking of hydrogen bonds and the release ofamylose and amylopectin into the surrounding area [12]ese results were in agreement with other studies that

claimed that the water diffusion rate was related to an in-crease in temperature whereas the initial water content andthe temperature were the principle factors influencing starchgelatinization [13]

Due to the nonsignificant difference in the rate constantof the temperature profile and water uptake between con-ventional cooking and the recommended cooking condition

105

95

85

75

65

55

45

35

25

Cooking time (min)

Tem

pera

ture

pro

file (

degC)

EC1EC2EC3

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40

(a)

L-MC1L-MC2M-MC1

M-MC2H-MC1H-MC2

105

95

85

75

65

55

45

35

25

Cooking time (min)

Tem

pera

ture

pro

file (

degC)

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40

(b)

Figure 1 Temperature profile during conventional cooking (a) and microwave cooking (b) EC conventional cooking using an electric ricecooker L-MC microwave cooking using low power level M-MC microwave cooking using medium power level and H-MC microwavecooking using high power level 1 low water ratio 2 medium water ratio and 3 high water ratio

20

18

16

14

12

100 2 4 6 8 10 12 14 16 18 20 22 24 26

Cooking time (min)

Wat

er u

ptak

e (g

g)

EC1EC2EC3

(a)

20

18

16

14

12

100 2 4 6 8 10 12 14 16 18 20 22 24 26

Wat

er u

ptak

e (g

g)

Cooking time (min)

L-MC1L-MC2M-MC1

M-MC2H-MC1H-MC2

(b)

Figure 2 Water uptake during conventional cooking (a) and microwave cooking (b) EC conventional cooking using an electric ricecooker L-MC microwave cooking using low power level M-MC microwave cooking using medium power level and H-MC microwavecooking using high power level 1 low water ratio 2 medium water ratio and 3 high water ratio


from the Riceberry rice producer EC3 was set as the controland the benchmark for the texture of cooked Riceberry riceVarious microwave cooking settings were carried out to findthe conditions that could provide a similar texture to EC3e texture profiles of cooked rice from conventional andmicrowave cooking are shown in Table 2

EC3 had values for hardness adhesiveness springinesscohesiveness and chewiness of 16203N minus67158 gsec 040046 and 3068 respectively (Table 2) Cooked rice obtainedfrom low rice-to-water ratios for each power level (L-MC1M-MC1 and H-MC1) was not significantly different inhardness In contrast the use of high rice-to-water ratios (L-MC2 M-MC2 and H-MC2) produced similar textureprofiles to that from EC3 Cooked rice with a high ratio ofwater produced a significantly soft texture e hardnessresult was attributed to both the amylose content and theamylose molecular size Li et al [23] reported that thehardness of cooked rice was determined by the innerstructure of the rice grain especially the proportion ofamylose branches with a degree of polymerization (DP theaverage number of monomeric units per molecules) from1000 to 2000 us a smaller amylose molecular size and ahigher proportion of amylose branches accelerated hardnessas these structural features affected the amylose leaching andthe degree of starch granule swelling during cooking

In the current study the microwave-cooked rice hadhigher adhesiveness than from conventional cooking sug-gesting that microwaving leached more components (totalsolid loss starch amylose and amylopectin) than fromconventional cooking because the microwave energy couldweaken the interaction between the amylose and amylopectinand improve their dispersion and separation Li et al [23]mentioned that stickiness of cooked rice was affected by thetotal amount of amylopectin the proportion of short amy-lopectin chains and the amylopectin molecular size in theleachate Furthermore the protein content in rice was con-sidered as a secondary factor affecting the starch molecularstructure and was related to cooked rice adhesiveness [5]

Conventionally cooked rice had the lowest springinessCooking at low and medium microwave power (L-MC1L-MC2 M-MC1 and M-MC2) produced no significantdifferences in springiness though at high microwave power(H-MC1) springiness was higher than that for H-MC2(Table 2) erefore the rice-to-water ratio may influencespringiness only under high-power conditions Cohesive-ness is the internal force holding rice together and indicatesthe amount of compression before breaking Microwavecooking at high power (H-MC2) tended to result in similarcohesiveness (047) and chewiness (3615) to those obtainedfrom the control (Table 2) It was noticeable that cohe-siveness and chewiness values decreased with an increase inthe rice-to-water ratio and these values varied depending onthe rice-to-water ratios for both low and high power ofmicrowave cooking ese results were in agreement withthe findings by Chusak et al [24] that cohesivenessdepended on the nature of the food and the external factorssuch as the moisture content and the temperature emicrowave-cooked rice had a low chewiness value similar tothe conventionally cooked rice when the high initial rice-to-

water ratio was used with high microwave power By de-creasing the rice-to-water ratio or the microwave power thechewiness was increased

Alteration of the textural characteristics of cooked riceby microwave cooking might be attributed to the reductionin the degree of starch gelatinization [24] e differentheating patterns could cause some modifications in thephysical structure of cooked rice Moreover the rate oftemperature increase may affect the kinetic constant the rateof starch hydrolysis and the texture and pasting propertiesdue to differences in the starch microstructure [12 25] etexture of cooked rice was influenced by the availability ofwater during the early stage of cooking which determinedthe hydration of the protein and the concentration of thedispersed and viscous phases of the starch [26]

Based on no significant difference in hardness and thesimilarity of the other texture attributes the options usingmicrowave cooking with high initial rice-to-water ratios (L-MC2 M-MC2 and H-MC2) were selected for further study

32 Comparison of Microwave Cooking and ConventionalCooking

321 Changes in Total Phenolic Content and AntioxidantActivity after Cooking After cooking under both conven-tional and microwave conditions the TPC of cooked rice(21441ndash24689mg GAE100 g db) decreased substantiallycompared to that of the rice grain (30222mg GAE100 gdb) as shown in Table 3 Conventional cooking (EC3)resulted in a significant loss of 2905 in the TPC in thecooked rice but the TPC loss was reduced by 1831 2021and 1886 for L-MC2 M-MC2 and H-MC2 respectively

e free radical scavenging activity of cooked rice wasmeasured using two different methods (DPPH and ABTSassays) to reduce the interference by other substances in thetest e scavenging activities of rice grains were 15709 and40703mgmiddotTE100 g db for DPPH and ABTS respectivelye DPPH scavenging activity of the cooked rice(11701ndash13715mgmiddotTE100 g db) was lower than ABTSscavenging activity (23005ndash31185mgmiddotTE100 g db) asshown in Table 3 e lower activity in the DPPH assays mayhave been due to chemical mechanisms e DPPH assaygenerally measures hydrophilic antioxidants while the ABTSassay determines both lipophilic and hydrophilic antioxidants[27] Compared to rice grains the loss of DPPH and ABTSactivities in conventionally cooked rice was 2552 and 4348whereas for microwave cooking the ranges were1269ndash1455 and 2338ndash2561 respectively ere was nosignificant difference in the TPC and antioxidant activities ofthe cooked rice when cooked at either low or high microwavepowere decrease in the antioxidant activities after cookingwas consistent with the reduction in the TPC ese resultsindicated that the TPC contributed to antioxidant activities inRiceberry rice After cooking the decrease in the TPC and thescavenging activity of conventionally cooked rice was greaterthan that from microwaving

e percentage loss could be related to cooking con-ditions such as the rice-to-water ratio heating source and


cooking time e decline has also been attributed to theoxidation of malvidin-3-glucoside and malvidin-35-diglu-cosides as a long conventional cooking time (37min) andcharacteristics of individual phenolic compounds could affectthe loss of antioxidants [14] e yield of anthocyanins in thegrape skin could be improved by using high microwaveenergy since heat treatment partially breakdowns an esterbond between the bound phenolic compounds and cell wallsto release some free phenolic compounds According to thedegradation pathway of malvidin-3-glucoside and malvidin-35-diglucoside under microwave treatment the formation ofanthocyanone A hydroxycoumarins dihydroxy phenyl-acetaldehyde and eight other compounds was detected in themicrowave-treated samples at 700W In contrast thosecompounds were not found in samples heated using a waterbath at 98plusmn 2degC e direct microwave effect formed hy-drogen peroxide resulting in BaeyerndashVilliger-type oxidationwhich was the main degradation pathway With this reactionanthocyanins were oxidized to form a derivative of thebenzoyloxyphenyl acetic acid ester which was named mal-vone en malvone was further hydrolyzed to form syringicacid and anthocyanone At the same time of oxidation theconventional degradation pathway of anthocyanins also oc-curred [28] erefore the higher remaining TPC and an-tioxidant activity in the microwave-cooked rice was attributedto the difference in the degradation pathway and the for-mation of new degraded products that may not be found inconventionally cooked rice

Another factor that may attribute to the great loss inconventionally cooked rice was from rice partially stuck and

burnt on the bottom of the container used in electric cookingas this would be the hottest area In contrast no rice layerwas formed or deposited on the microwave rice-steamingcontainer because no hot surface is required for microwaveheating erefore component leaching thermal decom-position and interaction mainly with the protein contentwere considered as possible factors responsible for the de-crease in the phenolic content of the pigmented rice duringconventional cooking In addition the presence of sugarsand phenolic acids could help to maintain anthocyaninstability [4] us the effect of cooking process on thedegradation mechanism of anthocyanin and phenolic acidshould be carefully identified and quantified with the ex-istent compounds in further study

322 Changes in Chemical Composition Changes in cookedrice composition such as the ash fat fiber protein andcarbohydrate contents after different cooking conditions areshown in Table 4 Under all cooking conditions there wereno significant difference in the ash or total dietary fibercontents However conventional cooking (control) resultedin the lowest protein content (1111) of any of the cookingconditions Notably there were no significant differences inthe protein content among all microwave-cooked ricesamplesis indicated that conventional cooking promotedthe leaching of protein from rice grains to the cooking waterwhile microwave cooking slowed down biochemical reac-tions and some changes in the molecular conformation ofthe protein [29]

Table 3 Total phenolic content and antioxidant activity of the rice grain and the cooked rice from conventional cooking and microwavecooking

Sample Total phenolic content(mg GAE100 g db)

Scavenging activity using DPPH(mg TE100 g db)

Scavenging activity using ABTS(mg TE100 g db)

Riceberry rice grain 30222plusmn 247a 15709plusmn 002a 40703plusmn 226aEC3 21441plusmn 478c 11701plusmn 264c 23005plusmn 1158cL-MC2 24689plusmn 468b 13498plusmn 121b 31185plusmn 290bM-MC2 24115plusmn 268b 13424plusmn 113b 30491plusmn 152bH-MC2 24522plusmn 197b 13715plusmn 099b 30280plusmn 1252b

Data expressed as meanplusmn standard deviation in duplicate a-cdifferent superscript letters indicate a significant (Ple 005) difference EC conventional cookingusing an electric rice cooker L-MCmicrowave cooking using low power level M-MC microwave cooking usingmedium power level andH-MCmicrowavecooking using high power level 1 low water ratio 2 medium water ratio and 3 high water ratio

Table 2 Texture profiles of cooked rice from conventional cooking and microwave cooking

Treatment Hardness (N) Adhesiveness (gsec) Springiness (minus) Cohesiveness (minus) Chewiness (minus)EC3 16203plusmn 408b minus67158plusmn 4264a 040plusmn 005d 046plusmn 000c 3068plusmn 358dL-MC1 18011plusmn 717a minus74154plusmn 4713a 056plusmn 007ab 051plusmn 003a 5362plusmn 1101abL-MC2 16672plusmn 462b minus88657plusmn 4281b 054plusmn 005b 049plusmn 001b 4460plusmn 639cM-MC1 17613plusmn 542a minus82866plusmn 8100b 053plusmn 009bc 050plusmn 001ab 4766plusmn 982bcM-MC2 16635plusmn 798b minus101326plusmn 18222c 053plusmn 006bc 049plusmn 001b 4439plusmn 747cH-MC1 17521plusmn 822a minus106435plusmn 6701cd 062plusmn 008a 050plusmn 002ab 5620plusmn 1207aH-MC2 16235plusmn 586b minus111802plusmn 5360d 047plusmn 004c 047plusmn 001c 3615plusmn 520d

Data expressed as meanplusmn standard deviation in triplicate andashddifferent superscript letters indicate a significant (Ple 005) difference EC conventional cookingusing an electric rice cooker L-MCmicrowave cooking using low power level M-MC microwave cooking usingmedium power level andH-MCmicrowavecooking using high power level 1 low water ratio 2 medium water ratio and 3 high water ratio


Using high microwave power caused a significant re-duction in the fat content of the cooked rice compared withthe other conditions is might have been directly corre-lated to the loss of the detached oil bodies through a smallopening between the paleal and lemma during the hydrationof rice [30] e conventionally cooked rice had a highproportion of carbohydrate (7823) since its proteincontent was more affected than by microwave cooking

e GI is a physiological measure used to classify foodrich in carbohydrate based on the foodrsquos potential to raisethe blood glucose level Rice is considered to be a high-GIfood (GIgt 70) e differences in the starch digestibility ofcooked rice have been attributed to the disruption of starchgelatinization structure modification breakdown of the cellwall and protein denaturation [31] In the current study theGI values of all cooked rice samples were in the range7300ndash7311 and were not significantly different us as theGI was greater than 70 the cooked Riceberry rice wasclassified as having a high glycemic index Cooking possiblyincreased the rate of hydrolysis and the gelatinized starch ofthe freshly cooked rice was readily available for the enzy-matic attack because cooking increased the space aroundcrystallites through the swelling of starch grains and de-creased the continuity in the construction of protein bychanging the structure of starch molecules [22 32] uscooking using the electric cooker or the microwave oven didnot produce a significant change in the GI is coincidedwith that reported by Chapagai et al [33] that there were noGI differences among different cooked rice samples althoughthere were some differences in the amount of amylose-lipidcomplexes

4 Conclusion

In general rice is conventionally cooked in an electriccooker However by changing to microwave cooking therate constant of the temperature profile and increased wateruptake during cooking were significantly improved einitial rice-to-water ratio significantly influenced the textureof the cooked rice Both microwave cooking and conven-tional cooking produced similar results for the texture totalstarch content and GI In terms of bioactive compoundsmicrowave cooking could retain higher levels of TPC andantioxidant activities in the cooked rice than from con-ventional cooking erefore microwave cooking could berecommended for Riceberry rice which has an inherent high

antioxidant activity is alternative to the conventional ricecooker method could reduce the cooking time by 14ndash18and preserve nutritional quality Consumption of Riceberryrice cooked in a microwave oven could maximize healthbenefits like antioxidant activity while producing a com-parable textural quality

Data Availability

e data used to support the findings in this study areavailable from the corresponding author upon request

Conflicts of Interest

e authors have no conflicts of interest

Acknowledgments

Financial support was provided by the Kasetsart UniversityResearch and Development Institute (KURDI) Bangkokailand and the Department of Product Development andFaculty of Agro-Industry Kasetsart University

References

[1] F Ayimbila and S Keawsompong ldquoEffect of processingprocedures on in vitro digestibility and colonic fermentationof Riceberry ricerdquo Journal of Microbiology Biotechnology andFood Sciences vol 8 no 3 pp 940ndash946 2018

[2] P Wiriyawattana S Suwonsichon and T SuwonsichonldquoEffects of drum drying on physical and antioxidant prop-erties of riceberry flourrdquo Agriculture and Natural Resourcesvol 52 no 5 pp 445ndash450 2018

[3] M Peanparkdee R Yamauchi and S Iwamoto ldquoCharac-terization of antioxidants extracted from ai riceberry branusing ultrasonic-assisted and conventional solvent extractionmethodsrdquo Food and Bioprocess Technology vol 11 no 4pp 713ndash722 2017

[4] S Yamuangmorn B Dell and C Prom-u-thai ldquoEffects ofcooking on anthocyanin concentration and bioactive anti-oxidant capacity in glutinous and non-glutinous purple ricerdquoRice Science vol 25 no 5 pp 270ndash278 2018

[5] H Li and R G Gilbert ldquoStarch molecular structure the basisfor an improved understanding of cooked rice texturerdquoCarbohydrate Polymers vol 195 pp 9ndash17 2018

[6] M Tamura T Nagai Y Hidaka T Noda M Yokoe andY Ogawa ldquoChanges in histological tissue structure and

Table 4 Chemical composition of the Riceberry rice grain (Oryza sativa L) and the cooked rice from conventional cooking and microwavecooking

Sample Ash content ( db) Fat ( db) Fiber ( db) Protein( db)

Carbohydrate( db)

Total starch( in db) Estimated GI

Raw riceberry rice grain 148plusmn 002a 327plusmn 002a 246plusmn 004a 1231plusmn 003a 7289plusmn 003d mdash mdashEC3 144plusmn 001a 330plusmn 003a 229plusmn 007a 1111plusmn 007b 7823plusmn 018a 7527plusmn 184a 7300plusmn 004aL-MC2 147plusmn 002a 323plusmn 003a 244plusmn 016a 1203plusmn 030a 7691plusmn 016c 7427plusmn 126a 7311plusmn 043aM-MC2 145plusmn 000a 322plusmn 004a 232plusmn 009a 1211plusmn 026a 7756plusmn 024b 7529plusmn 084a 7301plusmn 029aH-MC2 147plusmn 001a 306plusmn 010b 232plusmn 009a 1201plusmn 004a 7748plusmn 013b 7590plusmn 075a 7301plusmn 083a

Data expressed as meanplusmn standard deviation in triplicate a-ddifferent superscript letters indicate a significant (Ple 005) difference EC conventional cookingusing an electric rice cooker L-MCmicrowave cooking using low power level M-MC microwave cooking usingmedium power level andH-MCmicrowavecooking using high power level 1 low water ratio 2 medium water ratio and 3 high water ratio


textural characteristics of rice grain during cooking processrdquoFood Structure vol 1 no 2 pp 164ndash170 2014

[7] Y H Shinde A Vijayadwhaja A B Pandit and J B JoshildquoKinetics of cooking of rice a reviewrdquo Journal of Food En-gineering vol 123 pp 113ndash129 2014

[8] G Mishra D C Joshi D Mohapatra and V B BabuldquoVarietal influence on the microwave popping characteristicsof sorghumrdquo Journal of Cereal Science vol 65 pp 19ndash242015

[9] A S T Ferreira J Naozuka G A R Kelmer andP V Oliveira ldquoEffects of the domestic cooking on elementalchemical composition of beans species (phaseolus vulgarisl)rdquo Journal of Food Processing vol 2014 p 6 Article ID972508 2014

[10] S Subramaniam M H B Rosdi and U R KuppusamyldquoCustomized cooking methods enhance antioxidant anti-glycemic and insulin-like properties ofMomordica charantiaand Moringa oleiferardquo Journal of Food Quality vol 2017Article ID 9561325 9 pages 2017

[11] A M Kalla and R Devaraju ldquoMicrowave energy and itsapplication in food industry a reveiwrdquo Asian Journal of Dairyand Food Research vol 36 no 1 pp 37ndash44 2017

[12] M Gavahian Y-H Chu and A Farahnaky ldquoEffects of ohmicand microwave cooking on textural softening and physicalproperties of ricerdquo Journal of Food Engineering vol 243pp 114ndash124 2019

[13] K Kanjanapongkul ldquoRice cooking using ohmic heatingdetermination of electrical conductivity water diffusion andcooking energyrdquo Journal of Food Engineering vol 192pp 1ndash10 2017

[14] R Chatthongpisut S J Schwartz and J YongsawatdigulldquoAntioxidant activities and antiproliferative activity of aipurple rice cooked by various methods on human coloncancer cellsrdquo Food Chemistry vol 188 pp 99ndash105 2015

[15] B O Juliano e Rice Grain and its Gross CompositionChemistry and Technologypp 17ndash58 Elsevier AmsterdamNetherlands 2nd edition 1985

[16] J Wu J Chen W Liu et al ldquoEffects of aleurone layer on ricecooking a histological investigationrdquo Food Chemistryvol 191 pp 28ndash35 2016

[17] AOAC Official Methods of Analysis of the Association ofOfficial Analytical Chemists AOAC Washington DC USASeventeen edition 2000

[18] C Lerdluksamee K Srikaeo J A M Tutusaus andJ G Dieguez ldquoPhysicochemical properties and starch di-gestibility of Scirpus grossus flour and starchrdquo CarbohydratePolymers vol 97 no 2 pp 482ndash488 2013

[19] P A Sopade and M J Gidley ldquoA rapid in-vitro digestibilityassay based on glucometry for investigating kinetics of starchdigestionrdquo StarchmdashStarke vol 61 no 5 pp 245ndash255 2009

[20] H Ekka D Padhee L Sharma M Diwakar R Lahari andS Tiwari ldquoStudy of cooking quality of selected varieties of riceat varying temperature using induction heaterrdquo InternationalJournal of Food Science and Nutrition vol 1 no 2 pp 4ndash72016

[21] A Briffaz P Bohuon J-MMeot M Dornier and C MestresldquoModelling of water transport and swelling associated withstarch gelatinization during rice cookingrdquo Journal of FoodEngineering vol 121 pp 143ndash151 2014

[22] M He C Qiu Z Liao Z Sui and H Corke ldquoImpact ofcooking conditions on the properties of rice combinedtemperature and cooking timerdquo International Journal of Bi-ological Macromolecules vol 117 pp 87ndash94 2018

[23] H Li J Yang M Gao J Wang and B Sun ldquoWashing ricebefore cooking has no large effect on the texture of cookedricerdquo Food Chemistry vol 271 pp 388ndash392 2019a

[24] C Chusak J A Y Ying J L Zhien et al ldquoImpact of Clitoriaternatea (butterfly pea) flower on in vitro starch digestibilitytexture and sensory attributes of cooked rice using domesticcooking methodsrdquo Food Chemistry vol 295 pp 646ndash6522019

[25] L Yu M S Turner M Fitzgerald J R Stokes and T WittldquoReview of the effects of different processing technologies oncooked and convenience rice qualityrdquo Trends in Food Scienceamp Technology vol 59 pp 124ndash138 2017

[26] H Li J Yang S Yan N Lei J Wang and B Sun ldquoMolecularcauses for the increased stickiness of cooked non-glutinousrice by enzymatic hydrolysis of the grain surface proteinrdquoCarbohydrate Polymers vol 216 pp 197ndash203 2019b

[27] W Daiponmak C Senakun and S Siriamornpun ldquoAnti-glycation capacity and antioxidant activities of differentpigmented ai ricerdquo International Journal of Food Science ampTechnology vol 49 no 8 pp 1805ndash1810 2014

[28] M Zhao Y Luo Y Li et al ldquoe identification of degradationproducts and degradation pathway of malvidin-3-glucosideand malvidin-3 5-diglucoside under microwave treatmentrdquoFood Chemistry vol 141 no 3 pp 3260ndash3267 2013

[29] S Zhao S Xiong C Qiu and Y Xu ldquoEffect of microwaves onrice qualityrdquo Journal of Stored Products Research vol 43no 4 pp 496ndash502 2007

[30] S J Kale S K Jha G K Jha J P Sinha and S B Lal ldquoSoakinginduced changes in chemical composition glycemic indexand starch characteristics of basmati ricerdquo Rice Sciencevol 22 no 5 pp 227ndash236 2015

[31] S Wang P Li T Zhang J Yu S Wang and L Copeland ldquoInvitro starch digestibility of rice flour is not affected by methodof cookingrdquo Lwt vol 84 pp 536ndash543 2017

[32] M Tamura J Singh L Kaur and Y Ogawa ldquoImpact of thedegree of cooking on starch digestibility of rice - an in vitrostudyrdquo Food Chemistry vol 191 pp 98ndash104 2016

[33] M K Chapagai N A Bakar R A Jalil et al ldquoGlycaemicindex values and physicochemical properties of five brownrice varieties cooked by different domestic cooking methodsrdquoFunctional Foods in Health and Disease vol 6 no 8 p 5062016


stone fires electric cookers microwave ovens inductioncookers and other high-tech appliances Shinde et al [7]reported 10ndash25 variation in the operation efficiency ofconventional cooking Currently more emphasis is placedon energy conservation being environmental friendly andon hygienic production thus microwave heating has be-come more attractive than traditional heating Microwavesare known to generate heat inside the penetrated mediumbecause of the induced molecular friction in an alternatingelectromagnetic field e increased interest in microwavingfoods has been encouraged by its faster heating featureslower energy consumption convenience and maintenanceof nutritional integrity [8] e Ca K Mg P and Zncontents of jalo and black bean species increased after do-mestic microwave cooking while the contents of Cu Fe andS did not change [9] e antioxidant activity of somevegetables such as Momordica charantia and Moringaoleifera could be also enhanced by microwave heating [10]Microwaves are mostly used for drying blanching andpasteurization in food industries e catering industry usesmicrowave ovens mainly for reheating preprepared products[11] Recently traditional thermal processing has beenreplaced by microwave cooking due to the accelerated paceassociated with the modern lifestyle

Conventional cooking using an electric cooker involvesheating as a combination of conduction (between the heaterand the bottom of the container) convection (between theliquid phase and the container) and convection (betweenthe water and rice grains) In contrast microwave cookinggenerated heat by dipolar rotations and ionic interactions[5 12 13] ese different heating mechanisms could affectthe quality of the cooked food For example the firmnessand chewiness of steamed nonglutinous rice were higherthan those from boiling in an electric cooker Interestinglythe anthocyanins in pigmented rice decreased by around80 after cooking in an electric cooker whereas the phenoliccompounds declined by 54 [4] Ayimbila and Keawsom-pong [1] demonstrated that the slow digestion of the starchin Riceberry rice was accelerated depending on the cookingmethod e differences in the starch fractions were at-tributed to the processing conditions and variation in theamount of water which played a crucial role in starch ge-latinization and retrogradation mechanisms during cookingand storage Besides the hydrolysate of Riceberry rice sig-nificantly enhanced the growth of probiotic strains during invitro fermentation

Chatthongpisut et al [14] reported that the degradationpathway of anthocyanins under microwave heating wasdifferent from conventional heating resulting in differentdegraded products Although extremely high-temperaturetreatment promoted the degradation of anthocyanins inaipurple rice it generated phenolic compounds such asprotocatechuic acid (PCA) vanillic acid and ferulic that hadan antiproliferative effect on Caco-2 cells After cooking theconcentration of PCA significantly increased approximately121ndash3 times compared with the raw rice Yamuangmornet al [4] reported that the antioxidant capacity of cookedpurple nonglutinous rice contrasted in its anthocyaninconcentration indicating that there could be a higher

concentration of other antioxidant compounds after cook-ing For this reason cooking Riceberry rice using micro-waves could result in different profiles of anthocyaninsphenolic compounds and biological activity compared withusing an electric cooker

erefore this study aimed to evaluate possible alter-native cooking methods for Riceberry rice in a domesticmicrowave oven and the effect of microwave cooking onantioxidant activities and qualities e study outcomeswould facilitate decisions on cooking rice to maximize itsnutrient content for everyday consumption

2 Materials and Methods

21 Materials and Chemical Reagents e Riceberry riceused was a commercial product purchased from a localmarket in ailand and stored in a cool room until use Adomestic microwave oven with a frequency of 2450MHz(MP-94825S LG Electronics Inc Korea) and an electriccooker (Model Sharp KSH-D06 Federal Electric Corp Ltdailand) were used for this study

All chemical reagents consisting of gallic acidFolinndashCiocalteu reagent 22-diphenyl-1-picrylhydrazyl(DPPH) 6-hydroxy-2578-tetramethylchromane-2-car-boxylic acid (Trolox) 22-azino-bis-3 ethylbenzothiazoline-6-sulphonic acid diammonium salt (ABTS) methanol andethanol were of analytical grade and purchased from Sigma-Aldrich (St Louis MO USA)

22 Sample Preparation and Rice Cooking Cooked rice wasprepared in three steps namely washing cooking andwarming A classical cooking procedure for rice was chosenfor the preliminary study Rice grains were washed threetimes (1min each time) to eliminate all dirt on the grainsTwo different cooking methods were used microwavecooking using a domestic microwave oven and conventionalcooking using an electric cooker When the cooker auto-matically shifted to the warm setting the rice was held for10min at that setting according to the cooker manualwhereas the rice was allowed to stand for 5min after mi-crowave cooking

e experiment used a completely randomized designere were nine treatments involving either conventionalcooking or microwave cooking For conventional cooking100 g of Riceberry rice grains were prepared in a cookerRice-to-water ratios of 1 18 1 20 and 1 22 (w v) werepreliminarily determined to obtain the optimal quality withcooking times of 32min 34min and 37min respectivelyand designated as EC1 EC2 and EC3 respectively Formicrowave cooking 50 g of rice was placed in a microwaverice-steaming container (Model Sistema 26 L New Zealand)with a limited water ratio en the rice-steaming containerwas placed on the center of the turntable plate in the mi-crowave chamber and heated using three power levels(360W 600W and 900W) Rice-to-water ratios of 1 28(L-MC1) and 1 30 (L-MC2) were used for microwavecooking at 360W At 600W the rice-to-water ratio was






W1 (1)















(2)



GIavg 3921 + 0803HI90( 1113857 +(3951 + 0573HI)( 1113857

21113890 1113891

(3)














105

95

85

75

65

55

45

35

25

Cooking time (min)

Tem

pera

ture

pro

file (

degC)

EC1EC2EC3

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40

(a)

L-MC1L-MC2M-MC1

M-MC2H-MC1H-MC2

105

95

85

75

65

55

45

35

25

Cooking time (min)

Tem

pera

ture

pro

file (

degC)

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40

(b)


20

18

16

14

12

100 2 4 6 8 10 12 14 16 18 20 22 24 26

Cooking time (min)

Wat

er u

ptak

e (g

g)

EC1EC2EC3

(a)

20

18

16

14

12

100 2 4 6 8 10 12 14 16 18 20 22 24 26

Wat

er u

ptak

e (g

g)

Cooking time (min)

L-MC1L-MC2M-MC1

M-MC2H-MC1H-MC2

(b)































4 Conclusion



Data Availability




Acknowledgments


References









Carbohydrate( db)






































W1 (1)















(2)



GIavg 3921 + 0803HI90( 1113857 +(3951 + 0573HI)( 1113857

21113890 1113891

(3)














105

95

85

75

65

55

45

35

25

Cooking time (min)

Tem

pera

ture

pro

file (

degC)

EC1EC2EC3

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40

(a)

L-MC1L-MC2M-MC1

M-MC2H-MC1H-MC2

105

95

85

75

65

55

45

35

25

Cooking time (min)

Tem

pera

ture

pro

file (

degC)

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40

(b)


20

18

16

14

12

100 2 4 6 8 10 12 14 16 18 20 22 24 26

Cooking time (min)

Wat

er u

ptak

e (g

g)

EC1EC2EC3

(a)

20

18

16

14

12

100 2 4 6 8 10 12 14 16 18 20 22 24 26

Wat

er u

ptak

e (g

g)

Cooking time (min)

L-MC1L-MC2M-MC1

M-MC2H-MC1H-MC2

(b)































4 Conclusion



Data Availability




Acknowledgments


References









Carbohydrate( db)




































(2)



GIavg 3921 + 0803HI90( 1113857 +(3951 + 0573HI)( 1113857

21113890 1113891

(3)














105

95

85

75

65

55

45

35

25

Cooking time (min)

Tem

pera

ture

pro

file (

degC)

EC1EC2EC3

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40

(a)

L-MC1L-MC2M-MC1

M-MC2H-MC1H-MC2

105

95

85

75

65

55

45

35

25

Cooking time (min)

Tem

pera

ture

pro

file (

degC)

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40

(b)


20

18

16

14

12

100 2 4 6 8 10 12 14 16 18 20 22 24 26

Cooking time (min)

Wat

er u

ptak

e (g

g)

EC1EC2EC3

(a)

20

18

16

14

12

100 2 4 6 8 10 12 14 16 18 20 22 24 26

Wat

er u

ptak

e (g

g)

Cooking time (min)

L-MC1L-MC2M-MC1

M-MC2H-MC1H-MC2

(b)































4 Conclusion



Data Availability




Acknowledgments


References









Carbohydrate( db)





































105

95

85

75

65

55

45

35

25

Cooking time (min)

Tem

pera

ture

pro

file (

degC)

EC1EC2EC3

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40

(a)

L-MC1L-MC2M-MC1

M-MC2H-MC1H-MC2

105

95

85

75

65

55

45

35

25

Cooking time (min)

Tem

pera

ture

pro

file (

degC)

0 2 4 6 8 10 12 14 16 18 20 22 24 26 28 30 32 34 36 38 40

(b)


20

18

16

14

12

100 2 4 6 8 10 12 14 16 18 20 22 24 26

Cooking time (min)

Wat

er u

ptak

e (g

g)

EC1EC2EC3

(a)

20

18

16

14

12

100 2 4 6 8 10 12 14 16 18 20 22 24 26

Wat

er u

ptak

e (g

g)

Cooking time (min)

L-MC1L-MC2M-MC1

M-MC2H-MC1H-MC2

(b)































4 Conclusion



Data Availability




Acknowledgments


References









Carbohydrate( db)






























































4 Conclusion



Data Availability




Acknowledgments


References









Carbohydrate( db)


































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