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Kinetic of Color and Texture Changes in Rehydrated Figs

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Tarım Blmler Dergs Tar. Bl. Der. Derg web sayfası: Journal of Agrculural Scences Journal homepage: nec of olor and Texure hanges n Rehydraed gs TARIM
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Tarım Blmler Dergs Tar. Bl. Der. Derg web sayfası: Journal of Agrculural Scences Journal homepage: nec of olor and Texure hanges n Rehydraed gs TARIM BİLİMLERİ DERGİSİ JOURAL O AGRIULTURAL SIEES (5) 8- Sara ASARI a, eda MATOO-AZAD b, Ebrahm HOSSEII a, Asgar ARAHAY c, Gholam Hassan ASADI a a Deparmen of ood Scence and Technology, Scence and Research Branch, Islamc Azad Unversy, Tehran, IRA b ars Research ener for Agrculure and aural Resources, Zarghan, IRA c Deparmen of ood Scence and Technology, School of Agrculure, Shraz Unversy, Shraz, IRA ARTILE IO Research Arcle orrespondng Auhor: Ebrahm Hossen, E-mal: Tel: +98 () Receved: ebruary 4, Receved n Revsed orm: March 4, Acceped: Aprl 4 ABSTRAT Inermedae-mosure fgs obaned by rehydraon of dred fgs are more suable for drec consumpon. olour and exure are he mos mporan qualy arbues, whch nfluence he accepably of hs produc. In hs research he knec of color and exure changes n rehydraed fgs were suded as a funcon of me and emperaure (5-9 ). All huner colour parameers (L*, a* and b*) were used o esmae he exen of colour change durng rehydraon. Resuls ndcaed ha among dfferen knec models, a combned knec model provded he bes f. Moreover, exure developmen knecs over all emperaure ranges were sasfacorly descrbed by means of frs-order knec model compared wh second-order, Webull and Peleg models. Model parameers ncludng exure sofenng (k) and resdual consan (A) values were calculaed whch also confrmed he decrease n frmness of he dred fgs due o he plasczaon effec of waer nake. The Arrhenus model descrbed well he emperaure dependence of he reacon rae consan for colour and exure parameers. eywords: Dred fgs; Rehydraon; necs model; olour; Texure Rehdrasyona Tab Tuulan uru İncrde Renk ve Doku Değşm neğ ESER BİLGİSİ Araşırma Makales Sorumlu Yazar: Ebrahm Hossen, E-mal: Tel: +98 () Gelş Tarh: Şuba 4, Düzelmelern Gelş: Mar 4, abul: san 4 ÖZET Rehdrasyona uğramış kuru ncrlerden oralama neme sahp olanların doğrudan ükem mümkündür. uru ncrn renk ve dokusu bu ürünün kabul edleblrlğn ekleyen en öneml kale özellklerdr. Bu araşırmada rehdre edlmş ncrlern renk ve doku kneğ, zamanın ve sıcaklığın (5-9 ) fonksyonu olarak ele alınmışır. Rehdrasyon nec of olor and Texure hanges n Rehydraed gs, Ansar e al sırasındak renk değşmnn boyularını ahmn emede üm renk paramereler (L *, a * ve b * ) kullanılmışır. Sonuçlar, farklı knek modeller arasında, kombne knek modeln en uygun olduğunu gösermşr. Ayrıca, üm sıcaklık dağılımında doku gelşm kneğnn knc derece Webull ve Peleg modelne göre brnc derece knek modelle daha y açıklanableceğ görülmüşür. Doku yumuşaıcı (k) ve aık sabn (A) çne alan model paramereler hesaplanmış ve su alımının plaskleşme eks nedenyle kuru ncrlern sıkılığındak azalma ey edlmşr. Renk ve doku paramereler çn sıcaklığın reaksyon epk hız sabne olan bağımlılığını belrlemede Arrhenus model y sonuç vermşr. Anahar elmeler: uru ncr; Rehdrasyon; nek model; Renk; Doku Ankara Ünverses Zraa aküles. Inroducon g, one of he earles culvaed frus, s noe of he mos mporan dred producs wh several varees dred and sored for laer consumpom. I s probably orgnaed n Wesern Asa, and spread o he Mederranean (Slavn 6; Vnson 999). gs have a grea mporance n nuron due o beng mporan sources of carbohydraes. They conan essenal amno acds and are rch n vamns A, B, B and and mnerals (Veberc e al 8). The man exporers of dred fgs are Turkey, Uned Saes of Amerca and Iran, respecvely. Iran has approxmaely % of he oal producon of he world, and abou 9% of hs crop s sold as dred fru. Therefore, dred fgs have a hgh economc value for Iran Agrculure. Mos of he fgs n Iran are produced n he ars regon (AOSTAT ). The man problems wh dred fgs are a decrease n food qualy and safey due o hazardous mcroorgansms, aflooxn B and some sorage pess such as Ephesa or Ploda (Ozekn e al 6). Moreover, he process of dryng fgs may lead o mporan exural changes such as hardness and shrnkage, whch may have a negave mpac on her markeably (arahnaky e al ). One way o ncrease he consumer accepably of hs valuable agrculural commody s he producon of nermedae-mosure fgs (Press fgs) n fg facores obaned by soakng of dred fgs n waer followed by condonng. The man problem wh hs produc s he rapd change of color afer producon whch caused he produc falure and may have a negave mpac on s markeably. Rehydraon, a par of ndusral processng sep for producon of hs new commody, can be effecve n conrollng he brownng and exure of he fnal produc. Rehydraon s a process of mosenng dry maeral (emena e al ). Rehydraon s usually carred ou by soakng he dry maeral n large amouns of waer, alhough, nsead of hs, some auhors have used oher lquds such as fru juces, sucrose, glucose or glycerol soluons. (Maldonado e al ; rokda & Marnos-ours 3). Rehydraon s nfluenced by several facors, grouped as nrnsc facors (produc chemcal composon, pre-dryng reamen, dryng echnques and condons, pos-dryng procedure, ec.) and exrnsc facors (composon of mmerson meda, emperaure, hydrodynamc condons) (Rasog e al 4). I s more desrable for he rehydraon process o be as fas as possble n order o rean suable srucural and chemcal characerscs and acqure beer qualy-reconsued producs (flavor, exure and nuronal qualy) (Sanjuan e al ). The knowledge of he rehydraon knecs of dred producs s mporan o opmze processes from a qualy vewpon snce rehydraon s a key qualy aspec for hose dred producs ha have o be reconsued before her consumpon (Garca-Pascual e al 6). Texure and colour characerscs are mporan qualy parameers whch are relaed o emperaure and he pre-dryng me of he rehydraon process. I s more desrable for colour properes o be as close o ha of he fresh produc as possble, so deermnng he mos precse rehydraon/dehydraon condons s of grea economc mporance (Morera e al 8). The majory of publcaons on he knecs of food color changes repor zero or frs order degradaon Tarım Blmler Dergs Journal of Agrculural Scences (5) 8-9 Rehdrasyona Tab Tuulan uru İncrde Renk ve Doku Değşm neğ, Ansar e al reacon knec. sha e al (6) used a frs-order knec model o descrbe he exural changes of poaoes durng hermal processng. The objecve of hs sudy was o sudy expermenally he colour and exural changes of dred fg durng rehydraon a dfferen emperaures. Dfferen knec equaons along wh her correspondng coeffcens were also evaluaed n order o descrbe exural and colour changes occurrng durng dred fg mmerson n waer.. Maeral and Mehods.. Raw maeral Dred fgs (Sabz-culvar) were purchased from Esahban g Research saon (ars provnce, souhern Iran). They were packed n polyehylene bags and sored a 4 unl analyss. Inal mosure conen of dred fgs was 6.5% (dry bass)... Rehydraon expermens Dred fg samples, wh a fg o waer rao of :3 (w w - ), were rehydraed n dslled waer a consan emperaures (5, 6, 7, 8 and 9 ) for dfferen me nervals usng a hermosable waer bah (±. ). Afer rehydraon, he samples were removed from he bah and weghed afer blong wh ssue paper n order o remove superfcal waer. They were hen packed and sored unl mosure condonng. The mosure conen of samples was measured accordng o he AOA mehods (AOA 99)..3. olour measuremen olour of samples afer each rehydraon perod was evaluaed usng a modfed mehod of Yam & Papadaks (4). A dgal camera (anon Power- Sho A7, 8. megapxels), prevously calbraed wh sandard whe and black le was used o ake pcures, afer whch pcures of he samples were ransferred o a P for furher processng. Average values from expermenal daa a each me were deermned. Usng Adobe Phooshop S5 sofware, he colour parameers of L* (lghness), a* (redness/ greenness) and b* (yellowness/blueness) were deermned n he Lab mode of he sofware. Toal colour dfference (DE*) was also calculaed a he end of each rehydraon perod wh respec o dred fgs, employng IELAB characersc parameers L*, a*, and b* as follows: L L a a b E* b Where; L, a and b refer o reference values,.e., colour parameers of dred fgs; and L, a and b refer o colour values a he end of varous me frames durng he rehydraon process. exp.4. Texure analyss Texure profle analyss exp (TPA) of rehydraed samples afer condonng were carred ou usng a exure analyzer (Texure Analyzer, TA Plus, Sable Mcrosysems, dx / d Surrey, x or England) x wh exp a load cell of 3 kg. Each sample correspondng o a rehydraon me afer mosure exp condonng ( was mn) subjeced o a double compresson force es usng a cylndrcal probe havng dmensons greaer han hose of he sample. Samples were or compressed o % of her orgnal hegh by wo consecuve compressons usng a cylndrcal probe of mm dameer a a ( T ) speed of exp mm/s. b( T ) The a wang me beween he wocycles of he TPA es was s. The compresson force versus me was used o calculae exure profle parameers. /( Usng A Bhe Texure ) Exponen Le suppled by he manufacurer: hardness () was calculaed as n he maxmum force of he frs compresson cycle, ( X X, exp, pre) ompresson energy ( sec) was he area under force versus me unl maxmum / force obaned, he RMSE funcon = graden ( X (dmensonless), exp X, pre) calculaes he graden of he slope of he curve beween he wo seleced pons. All exural measuremens were performed ( X a, exp room X emperaure, pre) ( ± ) wh hree χ replcaons = of each sample. Z.5. Mahemacal modelng A A exp Ea RT.5.. necs of colour changes umerous references have examned he knecs of colour of food maerals n he leraure and he majory of hem repored zero-order (Equaon ) or frs-order (Equaon 3) degradaon reacon knecs. () Tarım Blmler Dergs Journal of Agrculural Scences (5) 8- nec E * of olor L and L Texure hanges n Rehydraed a a b b gs, Ansar e al () E L L a a () Texure parameer x represens () he oupu of a exure measuremen mehod such as peneromeer exp (3) force, rupure sress n a ensle (3) es, compresson force n exp hs curren sudy and so on. Oher Where; (+) and (-) ndcae formaon and researchers (Tjskens & Schjvens 987) have E* L L degradaon of any qualy exp parameer, respecvely. added anoher a a erm, consan b b δ (4) (resdual exure) Bu somemes relavely smple models descrbed o he model, whch accouns exp for he fnal remanng above (Equaons and 3) do no adequaely exure a he end of processng. The modfed- d x / d x or x exp represen he colour change phenomena. Therefore, frs order knec (5) d model s nroduced as follows x/ d x or x exp a combned knecs has been developed n whch (Equaon 6): colour change exp reacons are ( consdered mn) o conss exp (6) of wo sages: a frs phase of coloured exp ( mn) (6) E* L L compound a a b b E* L L () a a b b formaon ha follows a zero-order knec and a or Where; and represens (7) he nal exural second phase of coloured polymers decomposon value of raw maeral exp or and he exure sofenng rae no non-coloured compounds followng frs-order consan, respecvely (arahnaky () e al ). A knec. Accordng o hs model, he colour change ( T ) process exp b( T ) a dsecond-order (8) can be expressed as follows (Equaon 4) knec equaon was also employed x/ d x or x ( T ) exp exp ( ) a exp o model exure b T developmen (3) of samples durng exp (Garza e al 999): rehydraon process as follows (Equaon 7) exp ( mn) /( A B ) (Morera e al 8): (9) exp (4) /( A B ) exp (4) n or (7) Where; and ( X X, exp, pre ) () d x / d are he concenraons of colour x or x exp n Where; d ( X X, ) x/ d, exp pre (5) parameers a any me and nal concenraon represens x or he x exural exp value of raw / respecvely; maeral ( T ) RMSE = ( X, exp X, pre ) () exp s he zero-order knecs consan expa bme ( T ) ; a and s he correspondng rae / ( mn) consan (6) and s he frs-order knecs consan (mn - ) RMSE of he = ( model X, exp (mn X - exp )(, ) obaned mn) as a measure pre of he fness n Equaons 4. orrelaon coeffcens (R ) of of he expermenal daa a each nal each model ( X, exp X, pre ) mosure χ n accordance wh he nal values of conen /( A Bof ) samples. Webull model was X X (7) esmaed = parameers were used as used pre he bass o selec ( as he, exp prmary, ) or model o descrbe he effec of () he model whch Z χ bes descrbed he expermenal = heang me n on degradaon of frmness, as: ( X Z X, exp, pre) daa. ( T ) A Aexp exp b ( T E) a RT a ( T ) exp b( T ) (3) (8) A A exp a (8) / E RT a.5.. nec of exure changes RMSE = ( X, exp X, pre) Where; To descrbe /( Ahe Bexural ) changes durng he b(t) and a(t) are emperaure dependen (9) rehydraon E* L Lprocess of dred fgs, knec /( A B) coeffcens. Ths model s he cumulave form models a a b b X X () ( ncludng of Webull, exp, pre) frs n order knecs, second-order knecs, χ Webull ( X X, exp, pre) = () and Peleg models were employed. onlnear regresson analyss was performed wh he dsrbuon funcon, wh he a(t) n represenng ( he X shape Z X, exp facor, ) and he recprocal of pre b(t) s locaon facor (orradn & Peleg 6). / () / followng equaons. A When A n , exp he E sohermal a RT of he sem-logarhmc RMSE = ( X, exp X, pre) RMSE curve = has upper ( X, concavy exp X, pre) and () when n , he An approach exp frequenly appled n food curve shows a downward concavy. (3) The log-lnear sofenng sudes has been o express he change of ( X, exp X, pre) or frs a exure parameer χ x wh me by a frs order ( order X knecs, exp X, pre) was n fac he case when n=, = () relaon wh apparen Z exp rae consan χ k (Equaon 5) herefore he Webull model offers a grea of = (4) flexbly for (Verlnden 996). bologcal Z sysems (Yu e al ). Peleg model can also be used o descrbe exural A A exp Ea RT (3) dx / d x or x exp (5) changes A A by expa wo Eaparameer RT non-lnear (5) model (Peleg 988; Sacche e al 3): exp ( mn) (6) Tarım Blmler Dergs Journal of Agrculural Scences (5) 8- or ( T ) a b * b exp b( T ) (8) (7) exp ( mn) (6) () or (7) exp (3) E * L L ( T ) Rehdrasyona exp Tab b( Tuulan ) uru a a a b b () İncrde Renk ve Doku Değşm neğ, Ansar e al (8) exp (4) d /( A B ) x/ d x or x exp (5) () (9) 3. Resuls and Dscusson(9) wh he mnus ( ) sgn correspondng o loss n exp exp ( mn) 3.. Rehydraon curves (6) (3) phenomena ( Xknecs X and, exp, pre) he plus (+) sgn () correspondng o gan phenomena knecs. / The goodness of exp or (4) (7) f of he esed mahemacal RMSE = ( X, X, pre) () models o he expermenal daa was evaluaed from d he coeffcen of deermnaon (R ), sum square error ( X, exp (SSE; X, Equaon ( T ) x/ d exp b( T ) x a or x exp (5) pre) ), roo mean square (8) χ error = (RMSE; Equaon ) and he ch-square () (χ exp ( mn) (6) ; Equaon Z ) beween he predced and /( A B) (9) expermenal values. A A exp Ea RT (3) n or (7) (), exp, ) ( X X pre () ( T ) / exp b( T ) RMSE = ( (), exp, ) a (8) X X pre () X ( /( A X, exp B), pre) (9) χ = () () Z n ( X X, exp, pre) () Where; X A A,exp s he expermenal mosure conen; E RT a (3) X,pre s he predced mosure conen; / s he number RMSE = of observaons ( X, exp Xand, pre) z s he number of () consans (Doymaz 3). In order ( X, o exp prove X, pre he ) emperaure dependence of rae χ = consans, he Arrhenus equaon was appled () as follows: Z Rehydraon knec of food producs can be descrbed usng changes n mosure conen (calculaed as grams of waer/grams of solds) versus me of rehydraon (Markowsk & Zelnska ). gure shows mosure conen as a funcon of me for he fve rehydraon emperaures. All rehydraon curves demonsrae an exponenal rend wh hgh waer absorpon raes manly a he begnnng of he process. However, as rehydraon me progressed, he drvng force for waer ransfer decreased and he sysem slowly aaned equlbrum. Increasng he rehydraon emperaure from 5 o 9 ncreased boh he rehydraon rae and amoun of waer absorbed (Ansar e al 5). Ths behavor has been also repored by oher auhors for dfferen rehydraed producs such as apples, poaoes, carros, bananas, peppers, garlc, mushrooms, onons, leeks, peas, corn, pumpkn, omao, amaranh grans and chesnu (rokda & Marnos-ours 3; Reso e al 6; Morera e al 8). A A exp Ea RT (3) (3) Where; A corresponds o he knec parameers of each model (Machado e al 999; Sanjuan e al ; Turhan e al ); E a refers o he acvaon energy (kj mol - ); T s he absolue emperaure () and R s he unversal gas consan ( kj - mol - )..6. Sascal analyss Analyss of varance (One-way AOVA) of model parameers for colour and exure of samples rehydraed a dfferen emperaures was performed o deermne he presence of sgnfcan dfferences beween he means; Duncan mulple range ess was used o compare among he means usng IBM SPSS Sascs sofware, verson 9. gure - Rehydraon rae curve for dred fgs a dfferen emperaures (5-9 ). {Bars are ± sandard devaon} Şekl - arklı sıcaklıklarda (5-9 ) kuru ncr çn rehdrasyon oranı eğrs {barlar ± sandar sapmadır} Tarım Blmler Dergs Journal of Agrculural Scences (5) 8- nec of olor and Texure hanges n Rehydraed gs, Ansar e al 3.. olour analyss durng rehydraon olour s one of he mos mporan appearance arbues of food maeral, as nfluences consumer accepably. The change of produc colour as a resul of varous reacons such as non-enzymac brownng and pgmen desrucon may cause he produc o be rejeced by consumers (Maskan ; Wong & Sanon 993). Values of colour parameers for dred fgs were: L * =66.4, a * =5.7 and b * =4.49. The resuls of colour parameers (L*, a*, b* and DE*) afer rehydraon a dfferen emperaures (5-9 ) are presened n gures a and d. As can be seen n gure a, lghness (L*) decreased wh rehydraon me for all consdered emperaures. The fall of hs parameer n dred samples can be aken as a measuremen of brownng (Ibarz e al 999; Avla & Slva 999). Moreover, as can be noed n gure a, a decrease n lghness (L*) s srongly dependen on emperaure of rehydraon. Yellowness (a*) and Redness (b*) showed an oppose rend wh rehydraon me (gures b and c). Durng rehydraon a* values of dred fgs ncreased, whle b* values decreased. Smlar o L* values, he exen of change n a* and b* values are hgher n he samples rehydraed a hgher emperaures. The observed behavor for a* and b* values, as a funcon of rehydraon me, ndcaes an overall colour change from yellow owards reddsh-brownsh hues as prevously saed by omba e al (). Smlar resuls for he decrease n L*/b* values and an ncrease n a* were repored by many auhors n he dryng of kw frus (Maskan ), concenraon of fg juce (Mafoonazad e al ), rehydraon of chesnus (Morera e al 8), hermal reamen of peach jam (omba e al ), ec. gure -d shows DE* changes calculaed by use of Equaon, whch ndcaed he magnude of overall colour dfference beween dred and rehydraed fgs. DE* values ncreased wh rehydraon me a all emperaures wh he leas colour change observed a lower emperaures (5 ). omparng hese resuls wh hose repored by Morera e al (8) for rehydraon of chesnus confrmed a hgh dependency of DE* wh emperaure. In he presen sudy, varaon of colour parameers (L*, a*, b* and DE*) wh rehydraon me and emperaure were fed o a zero-, frsorder and combned knec models (Equaons -4) usng non-lnear regresson. The knec parameers, correlaon coeffcen (R ), and nal values of parameers ( ) esmaed are shown n Table -3. Regresson analyss revealed ha he compose model beer descrbed he expermenal daa of parameers L*, a*, b* and DE* compared wh zero- and frs-order models due o he hgh R and reasonable values obaned. However for L*, a* and b* values, boh zero- and frsorder reacon knec models can also be used adequaely afer combned knec model wh R values of (for L* values), (for b* values) and (for a* values) for he frs-order model; Bu as he R values of hese wo models were no sgnfcanly dfferen, deermnaon of he beer one afer combned knec model s mpossble. or DE*, zero order knec model demonsraed hgher R compared o frs order. However, he followng auhors saed ha he frs-order knec model was beer for b* and L* values of concenraed omao pase (Barrero e al 997), peach puree (Avla & Slva 999; Garza e al 999) and pear puree (Ibarz e al 999), whle Maskan () repored ha zeroorder knec model fed well wh he daa of a* values. Ths explans why auhors such as omba e al (), Mafoonazad e al () and Garza e al (999) used dfferen models as combned models o descrbe a seres of colour parameers. Moreover, as can be seen n Tables and, n all cases (DE*, L*, a* and b*) he zero-order model knec consan values ( ) were hgher han hose of frs-order mod
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