食品专业英文论文.docx

食品专业英文论文.docx

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食品专业英文论文

ExtractionofanthocyaninsfromredcabbageusinghighpressureCO2

ZhenzhenXua,b,c,JihongWua,b,c,YanZhanga,b,c,XiaosongHua,b,c,XiaojunLiao

a,b,c,

andZhengfuWanga,b,c

aCollegeofFoodScienceandNutritionalEngineering,ChinaAgriculturalUniversity,Beijing100083,China

bKeyLaboratoryofFruitandVegetableProcessing,MinistryofAgriculture,Beijing100083,China

cResearchCenterforFruitandVegetableProcessingEngineering,MinistryofEducation,Beijing100083,China

Received24November2009;

revised30March2010;

accepted2April2010.

Availableonline24April2010.

Abstract

TheextractionkineticsofanthocyaninsfromredcabbageusinghighpressureCO2（HPCD）againstconventionalacidifiedwater（CAW）wasinvestigated.TheHPCDtime,temperature,pressureandvolumeratioofsolid–liquidmixturevs.pressurizedCO2（R（S+L）/G）exhibitedimportantrolesontheextractionkineticsofanthocyanins.Theextractionkineticsshowedtwophases,theyieldincreasedwithincreasingthetimeinthefirstphase,theyielddefinedassteady-stateyield（y*）wasconstantinthesecondphase.They*ofanthocyaninsusingHPCDincreasedwithhighertemperature,higherpressureandlowerR（S+L）/G.Thegeneralmasstransfermodelwithhigherregressioncoefficients（R2>0.97）fittedthekineticdatabetterthantheFick’ssecondlawdiffusionmodel.AscomparedwithCAW,thetime（t*）toreachthey*ofanthocyaninsusingHPCDwasreducedbyhalfwhileitscorrespondingoverallvolumetricmasstransfercoefficientskL×afromthegeneralmasstransfermodelincreasedbytwofolds.

Keywords:

Redcabbage;Anthocyanins;HighpressureCO2;Thegeneralmasstransfermodel;TheFick’ssecondlawdiffusionmodel

Nomenclature

CAW

conventionalacidifiedwater

HPCD

highpressureCO2

FW

freshweight

A519

absorbanceat519nm

A519（pH1.0）

A519inpH1.0buffer

A519（pH4.5）

A519inpH4.5buffer

A

A519（pH1.0）−A519（pH4.5）

Mw

molecularweightofanthocyanin（=433.2g/mol）

DF

dilutionfactor（=10）

Ε

extinctioncoefficient（=31,600Lcm−1mol−1）

L

pathlength（=1cm）

V

finalvolumeofanthocyaninsliquidextracts（L）

M

weightofredcabbage（g）

V（S+L）

volumeofsolid–liquidmixture（mL）

VG

volumeofpressurizedCO2（mL）

VL

volumeofacidifiedwater（mL）

R（S+L）/G

volumeratioofsolid–liquidmixturevs.pressurizedCO2

T

time（minors）

Y

yieldofanthocyaninsinbulkliquidatgiventime（mg/100gFW）

y*

steady-stateyield（mg/100gFW）

t*

extractiontimetoreachy*（min）

kL×a

overallvolumetricmasstransfercoefficient（s−1）

S/L

ratioofsolidtoliquid（g/mL）

C

concentrationofsolute（mg/g）

D

diffusioncoefficientordiffusivity（m2s−1）

X

distanceofdiffusion（m）

Cs

concentrationofanthocyaninsinsolidphaseatgiventime（mg/g）

Cs,0

initialconcentrationofanthocyaninsatt=0（mg/g）

Cs,i

concentrationofanthocyaninsatgiventimet（mg/g）

steady-stateconcentrationofanthocyaninsatt

t*（mg/g）

Deff

effectivediffusivity（m2s−1）

λ

functionofradius（m−2）

v/v

volumetovolume

v/v/v

volumetovolumetovolume

RM

massratioofpressurizedCO2vs.solid–liquidmixture

R2

regressioncoefficient

DCO2

CO2density（g/mL）

SCO2

CO2solubility（g/100g）

Dwater

waterdensity（g/mL）

ML

massofwater（g）

MG

massofpressurizedCO2

RM

massratioofpressurizedCO2tosolid–liquidmixture

ArticleOutline

Nomenclature

1.

Introduction

2.

Methods

2.1.Preparationofredcabbage

2.2.Quantificationofanthocyanins

2.3.Extractionexperiments

2.3.1.HPCDextraction

2.3.2.CAWextraction

3.

Kineticmodels

3.1.Thegeneralmasstransferkineticmodel

3.2.TheFick’ssecondlawdiffusionmodel

4.

Resultsanddiscussion

4.1.Effectoftheextractiontimeontheyieldofanthocyanins

4.2.Effectoftheextractiontemperatureonthesteady-stateyieldy*ofanthocyanins

4.3.Effectoftheextractionpressureonthesteady-stateyieldy*ofanthocyanins

4.4.EffectoftheextractionR（S+L）/Gonthesteady-stateyieldy*ofanthocyanins

4.5.Modelingtheextractionkineticsofanthocyaninsfromredcabbage

5.

Conclusions

Acknowledgements

References

1.Introduction

Redcabbage（BrassicaoleraceaL.var.capitataf.rubra）belongstothefamilyofBrassicaceae,whichisanativevegetableoftheMediterraneanregionandsouthwesternEurope（Arapitsasetal.,2008）.Recently,ithasattractedmuchattentionbecauseofitsphysiologicalfunctionsandapplications.Anthocyaninsrichinredcabbageseemtoberesponsibleforthoseproperties（McDougalletal.,2007）.

Anthocyaninsareglycosidesofpolyhydroxyandpolymethoxyderivativesof2-phenylbenzopyryliumorflavyliumsalts（MazzaandMiniati,1993）.Besidesgivingcolortoplants,anthocyaninsalsohaveanarrayofhealth-promotingbenefits,astheycanprotectagainstavarietyofoxidantsthroughavariousnumberofmechanisms（Kongetal.,2003）.Healthbenefitsassociatedwithanthocyaninsincludeenhancementofsightacuteness,antioxidantcapacity,treatmentofvariousbloodcirculationdisordersresultingfromcapillaryfragility,vaso-protectiveandanti-inflammatoryproperties,inhibitionofplateletaggregation,maintenanceofnormalvascularpermeability,controllingdiabetes,anti-neoplasticandchemoprotectiveagents,radiation-protectiveagents,andpossiblyothersduetotheirdiverseactiononvariousenzymesandmetabolicprocesses（GiustiandWrolstad,2003）.Twenty-fouranthocyaninshavebeenseparatedandidentifiedinredcabbage,allhavingcyanidinasaglycon,representedasmono-and/ordi-glycoside,andacylated,ornot,witharomaticandaliphaticacids（Arapitsasetal.,2008）.

Anthocyaninsaresolubleinpolarsolvents,andtheyarenormallyextractedfromplantmaterialsbyusingmethanolthatcontainssmallamountofhydrochloricacidorformicacid（Kongetal.,2003）.Theextractionwithmethanolis20%moreeffectivethanwithethanol,and73%moreeffectivethanonlywaterinanthocyaninsextractionsfromgrapepulp（Metivieretal.,1980）.Acetonehasalsobeenusedtoextractanthocyaninsfromseveralplantsources,whichallowsanefficientandmorereproducibleextraction,avoidingproblemswithpectins,andpermitsamuchlowertemperatureforthesameconcentrationcomparedwithclassicalacidifiedaqueousormethanolicsolvents（Garcia-Vigueraetal.,1998）.Nowadays,theresiduesoforganicsolventssuchasmethanolandacetoneinthesemethodsareassociatedwithfoodsafety,sotheorganicsolventsarelimitedinfoodindustry.However,theconventionalacidifiedwater（CAW）extractionofanthocyaninsistime-consumingandinefficient,andhigherextractiontemperaturescausethedegradationofanthocyanins.Moreover,smallamountofacids,suchashydrochloricacidorformicacid,mayalsocausepartialortotalhydrolysisoftheacylmoietiesofacylatedanthocyaninspresentinsomeplants（Kongetal.,2003）.Therefore,itisakeyfocustodevelopnewextractionmethodswithfasterextractionratesandhigheryieldsinanthocyaninsextraction.Luque-Rodríguezetal.（2007）optimizedtheextractionconditionofanthocyaninsusingdynamicsuperheatedliquidextraction.ArapitsasandTurner（2008）proposedtheextractionofanthocyaninsfromredcabbageusingpressurizedsolventextraction.Corralesetal.（2009）studiedthehighhydrostaticpressureextractionofanthocyaninsfromgrapeskins.Thesestudies（[Arapitsasetal.,2008],[Luque-Rodríguezetal.,2007]and[Corralesetal.,2009]）indicatethatraisingextractionpressuremaybeanewmethodtoimproveextractionyieldandincreaseextractionrate.

CO2isanontoxicagentwithoutposinganyproblemsassociatedwithfoodsafety.TheexplosiveeffectofhighpressureCO2（HPCD）isfirstlydemonstratedtodisruptbacterialcellsbytherapidreleaseofgaspressurewiththeaimofcollectingcellcontents,numerousstudieshaveshowedtheefficacyofHPCDtoinactivatemicroorganismsandenzymesinbatch,semi-continuous,andcontinuoussystems（[Balabanetal.,1991],[Yoshimuraetal.,2002]and[Kincaletal.,2006]）.Withaneyeonthesimilarityindisruptingcellstructurebetweenmicrobialinactivationandsolid–liquidextraction,itisdeducedthatHPCDalsostrengthenedextractionprocessbyitssuperiorabilitiesincellmembranemodification,intracellularpHdecrease,disorderingoftheintracellularelectrolytebalance,removalofvitalconstituentsfromcellsandcellmembranes.However,thereisnostudyonHPCD-assistedextractionofanthocyaninstodate.LimitedstudiesinliteratureregardingtheeffectofHPCDonqualityofanthocyanin-containingfruitjuicesareavailable.DelPozo-Insfranetal.（2006）reportedthatnosignificantchangewasfoundinthetotalanthocyanincontent（TAcy）formuscadinegrapejuicespasteurizedbyHPCD.Tiwarietal.（2009）alsopointedoutthathighhydrostaticpressureandHPCDcausednodegradationofanthocyanins.

Kineticdataofextractionwerethemostimportantinformationinunderstandingtheextractionprocess.Thegeneralmasstransferkineticmodelandthediffusionmodelcanfitthenormalsolid–liquidextractionswell（[CacaceandMazza,2003],[Seikovaetal.,2004],[Handayanietal.,2008]and[Heetal.,2008]）.Inthisstudy,HPCDasanovelassisted-extractiontechniquewasusedtheextractionofanthocyaninsfromredcabbageforthefirsttime,theeffectsoftheimportantparameterssuchastheextractiontime,temperature,pressureandvolumeratioofsolid–liquidmixturevs.pressurizedCO2（R（S+L）/G）ontheextractionkineticswasdiscussed.TheextractionkineticswasfittedtothegeneralmasstransferkineticmodelandtheFick’ssecondlawdiffusionmodelforbetterunderstandingtheHPCDextractionprocess.

2.Met