Microgel-Stabilized Hydroxypropyl Methylcellulose and Dextran Water-in-Water Emulsion In fl uence of pH , Ionic Strength , and Temperat

《Microgel-Stabilized Hydroxypropyl Methylcellulose and Dextran Water-in-Water Emulsion In fl uence of pH , Ionic Strength , and Temperat》由会员上传分享，免费在线阅读，更多相关内容在学术论文-天天文库。

pubs.acs.org/LangmuirArticleMicrogel-StabilizedHydroxypropylMethylcelluloseandDextranWater-in-WaterEmulsion:InfluenceofpH,IonicStrength,andTemperatureJinglinZhang,LeiMei,PeihuaMa,YuanLi,YangYuan,Qing-ZhuZeng,andQinWang*CiteThis:Langmuir2021,37,5617−5626ReadOnlineACCESSMetrics&MoreArticleRecommendations*sıSupportingInformationABSTRACT:Astablewater-in-water(W/W)emulsionwasformedbymixingdextranandhydroxypropylmethylcellulose(HPMC)withadditionofβ-lactoglobulin(Blg)microgels.ThemicrostructureandstabilityoftheW/Wemulsionwereinvestigatedunderdifferentconditions.Themicrogelsaccumulat-ingattheliquid−liquidinterfaceledtoastableemulsionatpH3−5,wherethemicrogelscarriedpositivecharges.WhenthepHwasincreasedabovethepIofmicrogels(∼pH5),theemulsionwasdestabilizedbecausethemicrogelstendedtostayinthecontinuousphase(i.e.,dextran)ratherthanattheinterface.TheHPMC-in-dextranemulsionswerestableunderionicstrengthlevelsupto300mM.TheHPMC-in-dextranemulsionstabilizedbyBlgmicrogelswasthermallystable,andtheheattreatmentpromotedpartialBlgmicrogelparticle−particlefusiononthesurfaceofHPMCdropletsat90°C.ElectrostaticandhydrophobicinteractionsbetweendextranandHPMCphasewerefurtherinvestigatedtounderstandthemicrogels’accumulationattheliquid−liquidinterface.21.INTRODUCTIONtypicaloil−waterinterface),theparticlediametermustbeat3leastonemagnitudelarger,whichisr>100nm.Water-in-water(W/W)emulsionscanbeformedbymixingAccumulatingevidencesindicatePickeringstabilizationoftwoaqueoussolutionscontainingincompatiblepolymerswithW/Wemulsionsthroughadiverserangeofparticulateentitiesdropletsofoneaqueousphasedispersedinanotheraqueous45suchasbiopolymer-basedparticles,bacterialcells,andphase.W/Wemulsionshavepotentialsincost-effectivenon-fat6inorganicparticlesofvariousshapesandsizes.Amongformulationsforencapsulatingsensitivehydrophilicingredients1them,themostrelevancefood-basedsystemsareW/Wandreceivedagreatdealofattentionrecently.Commonly4,7emulsionsstabilizedbyproteinparticles.OneadvantageofusedmolecularsurfactantscannotstabilizeW/Wemulsionsusingproteinparticlesasastabilizeristhatprotein-basedagainstcoalescencebecausetheyaresmallrelativetotheDownloadedviaUNIVOFPRINCEEDWARDISLANDonMay16,2021at06:56:54(UTC).particlesmayhavefavorablepropertiesbecauseoftheirheatcorrelationlengthofthepolymersolutions,thuscannotspan8Seehttps://pubs.acs.org/sharingguidelinesforoptionsonhowtolegitimatelysharepublishedarticles.1sensitivity.Moreover,proteinparticlesarepHandionictheentirewater−waterinterface.Particlestabilizationeffectsstrengthresponsive.Theβ-lactoglobulin(Blg)microgelhavelongbeenstudiedfortheoil-in-water(O/W)emulsionsparticles(simplycalled“microgels”forshort)wereproducedknownasPickeringemulsions.Afteraparticlewithradiusrbyheat-inducedaggregationofthenativeBlgmoleculesunderattachestotheoil−waterinterface,thefreeenergyofspecificconditions,inwhichaggregationleadstotheself-spontaneousdesorption,ΔGd,canbeestimatedwiththeassemblyofproteinmoleculesintostablemicrogelparticlesoffollowingequation:9100−300nminsize,asextensivelydefinedelsewhere.An22importantdifferenceusingBlgmicrogelstostabilizeO/WandΔGrd=−πγOW(1|cosθ|)(1)W/Wemulsionsliesonthattheproteinmicrogelsarenon-dispersibleintheoilphaseofO/WemulsionsbutarewhereγOWistheoil−waterinterfacialtension,andθisthethree-phasecontactangleoftheparticlebetweenthesolidandtwoliquids.ThestabilityofO/WPickeringemulsionscanbeReceived:February18,2021understoodonthebasisofthefollowing:forr>10nmRevised:April20,2021particles,thebindingenergyisordersofmagnitudelargerthanPublished:April29,2021thethermalenergy(ifthethree-phasecontactangleisnottoofarawayfrom90°).However,forawater−waterinterfacewithanultralowinterfacialtension(100−1000timeslowerthana©2021AmericanChemicalSocietyhttps://doi.org/10.1021/acs.langmuir.1c004845617Langmuir2021,37,5617−5626

1Langmuirpubs.acs.org/LangmuirArticledispersibleinbothaqueousphasesofW/Wemulsions.solutionsindeionizedwater(DI),andthefinalconcentrationofGenerally,forproteins,thepreferenceisnotthesameforBlgstocksolutionwas2wt%.BlgsolutionwasacidifiedtopH5.85−thetwoaqueousphases,andthepartitioningofproteinsoccurs5.95using0.1MHClsolution.Microgelswereformedbysubmerging10ascintillationvialfilledwith10mLofBlgstocksolutioninahotintheaqueoustwo-phasesystems.waterbathat85°Cfor2hdirectlyfollowedbysubmersioninaniceW/WemulsionsstabilizedbyBlgmicrogelsorrelatedwaterbathfor20min.Sampleswerelyophilizedandstoredunder4particleshavebeenexaminedindifferenttwo-phaseaqueous°Cbeforeuse.TheBlgmicrogels(5wt%,astheproteinmoleculesystems.Blgfibrilswerefoundtobethemosteffectiveconcentration)stocksolutionwaspreparedbydispersingthe500mgstabilizerforPEO/dextranemulsionatpH7,whereasproteinoflyophilizedsamplesin10mLofDIwaterundergentlemagneticfractalaggregatesweremosteffectiveatpH3,mainlyduetostirringatroomtemperature(∼23°C)foratleast2h.Solutionswerethedifferentmorphologyoftheparticleshasvariedpreferencesstoredovernightat4°Ctoallowthehydrationofproteinmicrogels.attheinterfaceunderchangedpHconditions.11InanotherBeforethemicrogelswerecharacterizedormixedwithdextranandinvestigationitshowedthattheBlgmicrogelscanonlystabilizeHPMC,thesuspensionwassonicatedfor10−15minusing30%theamylopectin/xyloglucanemulsionsatpH<5becausetheamplitudepulsesevery1s.Particlesizesofdispersedmicrogelswereconfirmedat190−200nmwithdynamiclightscattering.Themicrogelshaveamuchstrongeraffinityforthedispersedphase16characterizationofBlgmicrogelscanbefoundinourpreviousstudythanthecontinuousphaseatahigherpHandthereforedonot12andintheSupportingInformation(FiguresS1andS2),about36%ofentertheW/Winterface.At10to15vol%additionofwheytheinitialproteinswereconvertedintoBlgmicrogels.proteinisolatemicrogels,phaseseparationbetweenaW/W2.3.PreparationofW/WEmulsion.Theemulsionsweresystemconsistingofwaxycornstarchandlocustbeangumcanpreparedbymixingaqueoussolutionsofdextran(0−20wt%),13beeffectivelyinhibitedatpH4,andtheaggregationofHPMC(1−10wt%),andBlgmicrogels(0−1wt%)atpH3bymicrogelswasobservedatthestarchphaseaswellasonthemagneticstirmixingfor30minat250rpm.TheorderofmixingdidW/Winterface.Thesefindingsallindicatedthatthenotsignificantlyinfluencethestructureoftheemulsion.AllaccumulationofthemicrogelsattheinterfaceispH-dependentpercentagesymbols(%)ofsolutionswerereferredtoweightpercentage(wt%)iflaterused.andofcrucialimportanceforstabilization.However,theThemassratiosofdextranandHPMCwereoptimizedforreasonwhytheproteinmicrogelshaveaffinityontheW/WobtainingstableW/Wemulsions.StableHPMC/dextran(1−2%/interfacewasstillstayingunconcluded.12%)ordextran/HPMC(2%/4.5%)emulsionswerepreparedwithHerein,weusedBlgmicrogelsasastabilizerforthe0.25−0.3%microgeladditiontostudytheemulsionstabilityunderstabilizationofanewfood-gradeW/Wsystemconsistingofdifferentenvironments.Thecriterionofstableemulsionswasdefined7dextranandhydroxypropylmethylcellulose(HPMC)andastheabsenceofavisiblelayerofapuredispersedphase.ThesystemtestedifthereisaspecificdrivingforceforBlgmicrogelswasconsideredunstableassoonasathin(<1mm)layerbecameaccumulatingontheW/Winterface.Phaseseparationoccursnoticeable.ItwasconsideredthattheformationofalayerofthepurebetweenHPMCanddextran,14suggestingthataW/Wcontinuousphasewasnotasignofdestabilizationoftheemulsiondroplets,butofcreamingorsedimentationofdropletsoftheemulsionmadeofdextranandHPMCmaybeafeasibledispersedphase.alternativeforthemodelsystemcontainingdextranandPEO,2.4.PhaseDiagram.ThephasediagramofamixtureofdextraninwhichPEOisnotgenerallyrecognizedassafe(GRAS)byandHPMCwasconstructedusingamethodreportedpreviously.17FDA.Thisstudyhadtwoobjectives.ThefirstobjectivewastoDifferentmassratios(1.98:0.02,1.9:0.1,1.7:0.3,1.5:0.5,1.2:0.8,1:1,investigatethestabilityofW/Wemulsionsunderseveral0.9:1.1,0.8:1.2,0.6:1.4,0.3:1.7,0.1:1.9,and0.02:1.98)ofstockemulsionandenvironmentalconditions,i.e.,microgelconcen-solutionsofdextran(10%)andHPMC(10%)wereintroducedto96-tration,polysaccharidescomposition,pH,ionicstrength,andwellplatesandmixedtoformW/Wemulsionsusingmicropipettes.temperature,togainabetterunderstandingoftheparametersEachwellwasthentitratedwithDIwateruntilemulsionthatcontrolthestabilizationofW/Wemulsions.Under-characteristics(i.e.,thepresenceofdroplets)werenolongerobservedstandingandcontrolofthesephasephenomenaareimportantbybrightfieldmicroscopy.Theexperimentwasperformedunderroomtemperature(∼23°C).Theconcentrationofeachphaseafterbecauseanexcessivephaseseparationmaycauseunacceptablethepointthatafurtherdilutionproducedadroplet-freemixturewaschangesintheappearanceorsensorypropertiesofproductsinrecordedasacriticalpoint.whichW/Wdispersionsexist.ThesecondobjectivewastoTielineswereestablishedbasedonareportedmethod18withcharacterizesurfacechargeandhydrophobicinteractionintheminormodifications.MixtureswithdifferentconcentrationsofsysteminordertoimproveourunderstandingoftheforcesdextranandHPMCwerepreparedinthetwo-phaseregion,andthedrivingmicrogelaccumulationontheW/Winterface.densityofthetopandbottomphaseswereanalyzedbyagravimetricmethod.Thiswasdoneusingavolumetricpipetteandpipettingaknownvolumeofsample(4mL)andmeasuringitsmass.Solutionsof2.MATERIALSANDMETHODSdifferenttotalmassratiosweretesteduntilbothtopandbottom2.1.Materials.DextranandHPMCwerepurchasedfromphaseshadthesamedensity(Figure1circleandtrianglesymbols),MilliporeSigma,Inc.(St.Louis,MO,USA).Thenominalweightwhichisarequirementforsolutionsonthesametieline.MixturesofaveragemolarmasswasMw=450,000−650,000g/molforthedextranandHPMConthesametielinehavethesameinterfacialdextranandMw=10,000g/molfortheHPMC.HPMChas1.8−2.0tension.molmethoxypermolcellulose(D.S.),0.2−0.3molpropyleneoxide2.5.MicrostructureObservationofW/WEmulsions.Thepermolcellulose(M.S.),viscosityof∼6cPin2wt%aqueousproteinmicrogelsandthedextranphaseinW/Wemulsionweresolutionsat20°C,andgelpointat58−64°C.Fluoresceinvisualizedseparatelywithconfocallaserscanningmicroscopyisothiocyanate-dextran(FITC-dextran,averagemolwtof500,000(CLSM)byutilizingdifferentfluorescentlabelingmethods.Theg/mol),fluorochromerhodamineBisothiocyanate(rhodamineB),microgelswerelabeledwiththerhodamineB(red)atafinalandsodiumdodecylsulfate(SDS;analyticalgradepowder)werealsoconcentrationof5ppm.ThedextranstocksolutionwaslabeledbypurchasedfromMilliporeSigma.addingasmallportion(0.5%)ofcommerciallyavailableFITC-labeled2.2.PreparationofProteinMicrogel.Wheyproteinisolatewasdextran(green)withthesamemolecularweightasthedextranstockkindlydonatedbyDaviscoFoodsInternational(LeSueur,MN,solution.USA),andfurtherextractionforBlgwasbasedonanestablishedConfocalimagesoftheW/Wemulsiondispersionswereobtained15procedure.ExtractedBlgwasusedtoprepareproteinstockat20°CwithaZeissLSM710confocalmicroscope(Zeiss,5618https://doi.org/10.1021/acs.langmuir.1c00484Langmuir2021,37,5617−5626

2Langmuirpubs.acs.org/LangmuirArticle3.RESULTSANDDISCUSSION3.1.PhaseDiagram.Inthisstudy,twoselectedpolysaccharides(i.e.,dextranandHPMC)wereimmisciblewhentheconcentrationoftheirmixturewasaboveacriticalpoint.Theimmiscibilitycouldbeexplainedbythehydrationdifferencebetweenthetwopolymersanddepletiononabasis19ofexcludedvolume.Becausethisisnotthefocusofthisstudy,thereasonsthatcausephaseseparationofthetwopolysaccharideswouldnotbefurtherdiscussedhere.AphasediagramwasproducedforthedextranandHPMCinthisstudybyanewmicroplate-basedphasediagramestimationassay(Figure1).Thenewmicroplate-basedestimationwasabletocreateaphasediagramwithinashorter17timewhileconsuminglesspolymer.Inaddition,themethodFigure1.PhasediagramforaqueousmixturesofdextranandHPMC.providedanalysisofphaseseparationevenforpointsonthefarThesolidlineindicatesthebinodal.Atielineisdrawnforillustrationendsofthephasediagramneartheaxes.Inourresults,theasdashedlines.Circleandtrianglesymbolsindicatecompositionslinearregression(R2=0.9251)hadabetterfitthanasecond-leadingtodextran/HPMCemulsionsorHPMC/dextranemulsions,orderpolynomialfit(R2=0.5989).Therefore,ourbinodallinerespectively.isalinearregressionlineofthe12criticalconcentrationpoints,insteadofaconcavecurve,whichiscommonlyseenintheliterature.WhentheconcentrationsofdextranandHPMCGermany).Anoilimmersionobjectivelens(63×/1.2NA)wasused.exceeded5.8and1.5%,respectively,phaseseparationoccurredTheincidentlightwasemittedbyalaserbeamat561nmforintheabsenceofstabilizers.Inthesemixtures,dropletsofonerhodamineBandat488nmforFITC.Thefluorescenceintensitywaspolysaccharidephasedispersedintheotherpolysaccharideasarecordedbetween568and650nmforrhodamineBandbetween492continuousphaseinamannerdependentonpolymerand544nmforFITC.Sampleswereinsertedbetweenaconcaveslidecomposition.ThecirclesymbolsinFigure1correspondtoandacoverslip.Theimagesweretakenafter12h,unlessotherwisethedextran-in-HPMCemulsions(dextran/HPMC),andtheindicated.Itwasconfirmedthattheuseoflabeleddextranandmicrogelshadnoinfluenceontheemulsions.trianglesymbolscorrespondtotheHPMC-in-dextran2.6.EmulsionStabilitytoEnvironmentalConditions.Inemulsions(HPMC/dextran).Thepolymercompositionsatordertoinvestigatethedropletmicrostructureandcreamingstabilitythesametielinehaveanidenticalinterfacialtension.Theofemulsionsunderdifferentenvironmentalconditions,thepH,ionicinterfacialtensionbetweentwoaqueousphasesincreaseswithstrength,andtemperaturewereadjustedasfollows:anincreasingpolymerconcentration7butremainsordersofpH:emulsionswereformedatpH3andadjustedtopH4,5,6,andmagnitudesmallerthanthatforO/Wemulsions,evenatthe7using0.1Mhydrochloricacid(HCl)solutionand/orsodiumhighpolymerconcentrationsstudied(circleandtrianglehydroxide(NaOH).symbols).Ionicstrength:emulsionswithdifferentionicstrengthswerepreparedbyaddingsodiumchloride(NaCl)solutiontoobtainafinal3.2.EffectoftheProteinMicrogelConcentration.concentrationof50,100,and300mMNaCl.StableW/WemulsionswiththeadditionofproteinmicrogelsTemperature:forthethermalstabilitystudy,each5mLofsampleswereachievedatpH3.0;therefore,thepHofdispersionwaswerepouredinto25mLofglassvialsandthensubmergedinawatersetat3.0unlessotherwisementioned.bathsetat25,60,or90°C.TheemulsionswereheldinthewaterFigure2showstheeffectoftheproteinmicrogelbathfor30minandthencooledtotheambienttemperature.concentration(Cpro)onthestabilityofHPMC/dextranTheemulsionsweretestedforthedropletmicrostructurebytheemulsionsafter1weekstandingattherefrigeratedtemper-CLSMshortlyaftertreatment.Forcreamingstability,emulsionswereature.Withoutanystabilizer,allemulsionsunderwentphasestoredattherefrigerationtemperatureandimagesweretakeneverydayforaperiodof1week.separationwithin1day.Withtheadditionofprotein2.7.ZetaPotentialMeasurement.Thezetapotentialsofmicrogels,thebehaviorsoftheemulsionsdependedonthemicrogelsandtwopolysaccharidephasesweredeterminedbetweenratioofHPMCanddextran.pH3and7bylaserdopplermicro-electrophoresisusingaZetasizerForemulsionscontaining12%dextranand1or2%HPMC,NanoZS(MalvernInstruments,Worcestershire,UK).EachsampletheadditionofproteinmicrogelsatCpro>0.05%stabilizedthewasmeasuredthreetimesindisposablefoldedcapillarycells(DTSemulsions,i.e.,theHPMCdropletsdidnotmergeorforma1070,MalvernInstrumentsLtd.,Worcestershire,UK)ataproteintransparentHPMCtoplayerforatleast1week.However,concentrationof0.1%orpolysaccharideconcentrationof1%.Atleastbecauseofthesizeofthedropletsandtheactionofbuoyancy,32runswereperformedpermeasurement.2.8.DemulsificationofW/WEmulsionsbySDS.Demulsifi-theemulsionsformedacreamedlayeratthetopandacationofW/WemulsionswasachievedbyintroducingSDSintothesubnatantaqueousphase.DependingontheCpro,thesystem.A0.5mLofstockSDSsolutionswasaddedto0.5mLofsubnatantwaseither(i)clear(forFigure2aCpro<0.1%oremulsionstoobtainafinalSDSconcentrationof2,4,and10mM.Figure2b<0.25%),suggestingacompleteadsorptionoftheThemixtureswerevortexedfor30sandtestedforadropletmicrogelstodropletinterfaces,or(ii)turbid,suggestingthatamicrostructurebyCLSMshortlyaftertreatment.Asacontrol,0.5mLfractionofthemicrogelsremainednon-adsorbedintheofDIwaterwasalsomixedwith0.5mLofemulsiontoexcludethecontinuousdextranphase.effectofdilutiononemulsiondroplets.AtahigherHPMCconcentration(2%)andalowerdextran2.9.StatisticalAnalysis.Allexperimentsandanalysiswereconductedinatleasttriplicatewithdatareportedasmean±standardconcentration(8%),theemulsionswerenotstableagainstdeviation.ExperimentalstatisticswereperformedusingtheMicrosoftcoalescenceforCpro≤0.5%,andthedestabilizationoftheExcel2016software.emulsiondropletsresultedinaclearHPMCphaseatthetop,5619https://doi.org/10.1021/acs.langmuir.1c00484Langmuir2021,37,5617−5626

3Langmuirpubs.acs.org/LangmuirArticlecomparisonofnumber-averagedropletdiameterfortwodifferentemulsionratios(Figure3b).Thenumber-averagedropletdiameterwasdeterminedbymanuallymeasuringthein-focusdropletsfromatleastthreeimages.Thediameterofdropletsin12%:2%emulsionsdecreasedwithincreasingCproupto0.3%,andfurtherincreasingtheCprodidnotsignificantlychangethedropletsize.TheemulsionsunderwentlimitedcoalescenceuntiltheCprowasincreasedabove0.3%.InthecaseoflimitedcoalescenceforO/Wemulsions,thereshouldnotbeexcessfreemicrogels;however,forW/Wemulsions,evenatlowCpro(e.g.,0.25%inFigure2b),excessfreemicrogelscouldbeobservedinthesubnatant.Withalargervolumefractionofthedispersedphase(8%:2%),thedropletsizewassignificantlylarger,whichmaybeexplainedbyadecreaseintheratioofmicrogels/interfacialarea.TheresultsindicatedthatthelimitedcoalescencetheoryshouldbeappliedtotheW/WPickeringemulsionwithfurthermodification.Nevertheless,ourfindingsontheeffectofmicrogels’concentrationwereconsistentwithothers’insimilarmicro-7gel-stabilizedW/Wemulsions.3.3.EffectofComposition.BytuningtheratioofHPMCanddextraninthemixture,weobtainedeitherHPMC-in-dextranordextran-in-HPMCemulsion.Theemulsionsofdifferentpolysaccharideratios(Cdex/CHPMC(%)1.5/8;1.5/2.9;8/2;12/2)showeddifferentstabilitieswiththesameconcentrationofproteinmicrogels(i.e.,0.5%)(Figure4).ThecreamingofHPMCdropletsbegantobevisibleafter1week(Figure4;twosamplesontheright),whereasthesedimentationofdextrandropletswascompletedforCdex/CHPMC(%)at1.5/2.9afteronly1day.CLSMimagestakenseveralminutesafterthepreparationofthesuspensionsshowedthatdispersionsofCdex/CHPMC(%)at1.5/8and1.5/Figure2.EmulsionsofHPMC/dextraninthepresenceofdifferent2.9compriseddextrandropletsdispersedintheHPMCconcentrationsofproteinmicrogels(Cpro=0,0.05,0.1,0.25,0.5,andcontinuousphase,whereassuspensionsofC/C(%)at1%;fromlefttoright)after1weekstanding.(a)C=12%anddexHPMCdex8/2and12/2wereHPMCdropletsdispersedindextran.BlgCHPMC=1%,(b)Cdex=12%andCHPMC=2%,and(c)Cdex=8%andCHPMC=2%.FITC-labeleddextran(green)wasonlyusedinthefirstmicrogelsweresituatedattheinterfaceoftwophasesexceptincolumntohelpvisualizethephaseseparation.Proteinmicrogelswerethesample1.5/2.9(inthedextranphase,Figure5).CompareddyedbyrhodamineB(red).withothercompositions,theratioof1.5/2.9wasclosertothebinodallineinthephasediagram,representingalowerinterfacialtensionbetweenthetwopolysaccharides.Therefore,indicatingthatphaseseparationoccurredevenwiththetheinterfacialtensionwasconsideredoneofdrivingforcesforadditionofproteinmicrogels.Theincreaseintheturbiditymicrogels’accumulationontheinterface.ofthebottomdextranlayerwascausedbythepresenceofTheemulsionscontainedseverallargeclustersofmicrogelsproteinmicrogelswithapreferenceforthedextranphase.thatclearlyprotrudedtowardthedextranphase(FigureS3),However,increasingtheproteinconcentrationtoCpro>0.5%thusindicatingthattheBlgmicrogelspreferentiallypartitionedpreventedthephaseseparation,andtheemulsionswerestableforatleast1week.tothedextranphaseinbothdextran/HPMCandHPMC/InPickeringemulsions,limitedcoalescenceoccursinthedextranemulsions.Thelargeclustersofmicrogelsmaybeemulsifier-poorregime,andthedropletsareinitiallyonlýformedthroughdepletioninteractionswhenenteringthe6partiallycoveredbytheemulsifierandundergocoalescenceinterface.Therelativepreferenceofthemicrogelsforoneofafteragitationstops.Thiscoalescenceleadstoaprogressivethetwophasesinfluencesthecontactangleofthemicrogelsatdecreaseintheoil/waterinterfacialareauntiltheadsorptiontheinterfaceandconsequentlythestabilityofW/Wemulsions.densityofstabilizersbecomesufficientlyhightopreventEmulsionsarewellknowntobemorestableifthestabilizerfurthercoalescence.20Consequently,thefinaldropletsizeisprefersthecontinuousphase.Therefore,inthisstudy,HPMC/inverselyproportionaltotheinitialstabilizerconcentration.21dextranemulsionsareexpectedtobemorestable.Inthepresenceofanexcessofastabilizer(emulsifier-richInterestingly,forsample1.5/8,evenwhencoveredwitharegime),théfinaldropletsizeoftheemulsionisvirtuallylayerofproteinmicrogels,thedropletsprecipitatedafter17independentoftheinitialstabilizerconcentrationandmainlyweek.AccordingtoNguyenetal.,theaggregationofdextrandependsonthestirringintensity,whichcontrolsdropletdropletsisthereasonfortherelativelyrapidsedimentation.fragmentation.ConsideringthatdextranhasahigherdensitythanHPMC,ThedependencyoftheW/WemulsiondropletsizeontogetherwiththepreferenceofBlgmicrogelsforthedextranproteinmicrogelconcentrationwasconfirmedwithCLSMphase,thesedimentationoraggregationofdextrandropletsimagesoftheemulsiondroplet(Figure3a)aswellasacanbeexplained.5620https://doi.org/10.1021/acs.langmuir.1c00484Langmuir2021,37,5617−5626

4Langmuirpubs.acs.org/LangmuirArticleFigure3.Effectofproteinmicrogelconcentration(Cpro)onemulsiondropletsize.(a)CLSMimagesofprotein(red)signalshowingtheeffectofCproonthedropletsizeforanemulsioncontaining12%dextranand2%HPMC.Thescalebarsare50μmforthefirstimageand20μmfortheothers.(b)Dependenceofnumber-averagedropletdiameterontheproteinconcentrationfortwoemulsioncompositions:Cdex=12%andCHPMC=2%orCdex=8%andCHPMC=2%.Theerrorbarsrepresentthestandarddeviationofthesizedistribution.3.4.EffectofpH.Wepreviouslyreportedthattheparticle16sizedistributionofBlgmicrogelsisdependentonpH.ThemicrogelsdisplayedapolyampholyticcharacterwithapIaround5.2.Theswellingofthesoftandpoorlycross-linkedmicrogelswasobservedwhenthepHwasfarfromthepI,indicatingaflexibleinternalstructure;increasingtheinternalchargedensitywouldcauseproteinstrandorchainrepulsionFigure4.EvolutionwithwaitingtimeofemulsionsformedbyHPMCwithinthemicrogels.anddextranmixturesatdifferentcompositionscontaining0.5%proteinmicrogels.Cdex/CHPMC(%)fromlefttoright:1.5/8,1.5/2.9,Figure6ashowstheeffectsofpHonthevisualappearance8/2,and12/2.ofHPMC/dextran(2%/12%)emulsionsafter1h,3days,and1week.UnderpH6and7,theemulsionscoalescedtoformFigure5.CLSMimagesofHPMCanddextranmixturesatdifferentcompositionscontaining0.5%proteinmicrogelsdyedbyrhodamineB(red)anddextranphasewasFITClabeled(green).Cdex/CHPMC(%)fromlefttoright:1.5/8,1.5/2.9,8/2,and12/2.5621https://doi.org/10.1021/acs.langmuir.1c00484Langmuir2021,37,5617−5626

5Langmuirpubs.acs.org/LangmuirArticleshowninFigure6b.Thesedextran/HPMCemulsionsweresituatedonthesametielineastheHPMC/dextran(2%:12%)emulsions;therefore,theinterfacialtensionwasthesameforbothemulsions.AtallpHlevels,rapidsedimentationofdextrandropletswasobserved,andthesedimentedlayershadthesameheightasthoseinthecontrolsample;therefore,distinguishingwhethertheemulsiondropletscoalescedwasdifficult.ThemicrostructuresofdextrandropletsandproteinmicrogelsatdifferentpHvaluesareshowninFigure7b.Becausebothemulsionshavethesameinterfacialtensionsandmicrogelconcentration,weexpectedtoobservesimilardropletsizeandadistinctlayerofthemicrogelonthesurface,asseenwiththeHPMC/dextranemulsion.However,theseaspectswereobservedonlyfordextran/HPMCemulsionatpH3.AtpH5.0,microgelsaggregatedsoaggressivelythattherewasinsufficienttimeforsphericaldextrandropletstoform.AtpH7.0,withoutthemicrogellayeronthesurface,thedextrandropletsremainedsmallbutsedimentedintothedextranbottomlayer.TheobservedrapidcreamingofHPMCdropletscoveredwithmicrogelscorrespondedtothefastsedimentationofFigure6.Evolutionwithwaitingtimeof(a)HPMC/dextran(2%/12%)and(b)dextran/HPMC(2%/4.5%)emulsionsatdifferentpHmicrogel-covereddextrandropletsatpH3,bothofwhicharevaluescontaining0(blank)or0.3%proteinmicrogels.causedbytheagglomerationofthedropletsintolargerclusters11thatcreamorsedimentrapidly.WhenthepHwasclosetothemicrogels’pI,thecreamingoftheHPMC/dextranphaseseparation,featuredbyacleartoplayeroftheHPMCemulsiondropletssloweddownbecauseproteinaggregatesphase.However,atpH<5,theBlgmicrogelsinhibitedtheledtotheformationofamicrogelnetworkinthecontinuousphaseseparation,andthecreamingofHPMCdropletswasphase.InducingproteinparticleaggregationtopreventobservedtobefasteranddenseratpH3thanatpH4and5.creaminghasalsobeenreportedforaPEO-in-dextranCLSMimagesoftheemulsionsweretakenrightaftertheemulsionwasmixedandrevealeddropletmorphologiesbeforeemulsionbydecreasingthenetchargedensityoftheprotein,22thecoalescenceoccurs(Figure7a).Distinctlayersofmicrogelsinaprocesscalledcoldgelation.wereobservedonthedropletsurfacesatpH3,4,and5,andThemicrogels’preferencetostayattheinterfaceorinthetheinterfaciallayersactasabarrierforinhibitingdropletdextranphasewasinfluencedbythepHofemulsionsystems.coalescence.However,atpH6and7,themicrogellayerontheSimilarpHeffecthasbeenshowninW/Wemulsionsofdropletsurfacesdisappeared,andthearrestedHPMCdropletsamylopectin(AMP)dropletsinacontinuousxyloglucan(XG)coalescedintolargerdroplets,thusultimatelyresultinginthephase,forwhichthesameBlgmicrogelsenteredtheinterface12formationofahomogeneousHPMClayer.IncreasingpHalsoatpH<5.ItisprobablybecausebelowacriticalpH,theincreasedtheFITCintensityofdextran,whichoverwhelmedmicrogelswillentertheinterfaceonlyiftheypartitionatleasttheproteinsignalinCLSMimages.Macroscopicpicturestoasmallextentintobothphases,whileathigherpHlevels,(Figure6a)showedthatthedextranbottomlayerwasturbid,BlgmicrogelshaveamuchstrongeraffinityforthedextranindicatingthatmicrogelssituatedinthedextranphaseunderphaseandthereforedonotentertheinterfacebetweenthetwopH6and7.incompatiblepolysaccharidesolutions.Blgmicrogelshave7TheeffectsofpHonthevisualappearanceofdextran/beenfoundmainlysituatedinthedextranphaseatpH>4.0.HPMC(2%:4.5%)emulsionafter1h,1day,and1weekareWemaytentativelyconcludethatmicrogelsentertheinterfaceFigure7.CLSMimagesof(a)HPMC/dextran(2%:12%)and(b)dextran/HPMC(2%/4.5%)emulsionswith0.3%proteinmicrogelsatdifferentpHvalues.TheemulsioniscoloredbythepresenceofFITC-dextran(green)andrhodamineBdyedproteinmicrogels(red).TheFITC-dextranconcentrationisidenticalinallsamples,buttheintensityofgreencolorisinfluencedbypH.5622https://doi.org/10.1021/acs.langmuir.1c00484Langmuir2021,37,5617−5626

6Langmuirpubs.acs.org/LangmuirArticleFigure8.CLSMimagesof0.3%microgelsin12%dextransolutions(top)andinHPMC/dextran(2%/12%)emulsions(bottom)atdifferentionicstrengths(mM).MicrogelsaredyedbyrhodamineB(red);insetsarerepresentativeimagesforobservingmicrogelcoverageonthesurface.Thescalebarsofinsetsare5μm.becausetheremightbeaninteractionbetweenmicrogelsandTheeffectsofionicstrengthonemulsionstabilityaftertheHPMCphaseatpH3.Itmayalsoberelatedtothestandingfor1h,3days,and1weekareshowninFigureS4.exposureofthehydrophobicunitsonthesurfaceofBlgWiththeadditionofNaCl,theemulsionsunderwentcreaming11faster.Thisfindingwasunexpected,accordingtotheresultsofmicrogels.BlgmicrogelshavebeenreportedtoundergoconformationalchangesexposingmorehydrophobicdomainspHeffect;weexpectedthatcreamingwouldbesloweddownunderpH3;16therefore,itispossiblethatthereishydrophobicbytheaggregationofproteinmicrogels.OnepossiblereasoninteractionsbetweenmicrogelsandHPMCatpH3.forthefastcreamingislikelycausedbytheaggregationof3.5.EffectofIonicStrength.Theeffectsofscreeningdroplets.electrostaticinteractionsbetweentheproteinmicrogelsand3.6.ThermalEffect.HeattreatmentofemulsionspolysaccharidephaseswereinvestigatedatpH3.0forstabilizedbythewheyproteinisknowntoacceleratecreamingemulsionswiththesamecompositionthroughtheadditionbecauseofproteinunfoldingandanincreaseinhydrophobicattractionamongdroplets.Therefore,thestabilityofW/Wofupto300mMNaCl.Tounderstandthebehavioroftheemulsionswasinvestigatedundertwodifferenttemperatures,mixtures,wefirststudiedthebehaviorofBlgmicrogelsasai.e.,temperaturesresultinginpartial(60°C)andfull(90°C)functionofionicstrengthinpuredextransolutionsatCdex=proteinunfolding.12%,correspondingtothepercentageofacontinuousphaseinAsshowninFigure9a,b,thermaltreatmentshadlittleeffectstheemulsions.Themicrogelconcentrationwassetat0.3%,oncreamingstabilityanddropletmicrostructureofthecorrespondingtothemaximumconcentrationofmicrogelsifemulsion,asexpected,becausetheproteinmicrogelsusedinallproteinspartitionedtothedextranphaseoftheemulsions.thesystemswereproducedfromathermaltreatment.TheThetoprowinFigure8showsCLSMimagesoftheinter-dropletinteractionsorbridgingofmicrogelswerenotmicrogelsinadextransolutionatdifferentionicstrengths.Intheblanksample,individualmicrogelscouldscarcelybeobservedbecauseoftheirnanoscalesize(∼200nm).Themicrogelsremainedhomogeneouslydistributedinthepresenceof50mMNaClbutformedflocsofdenseproteinclusterswhentheconcentrationofNaClwasincreasedto100mM.Increasingthesaltcontentto300mMdidnotmaketheseclusterstoassociateintolargerflocs,thusindicatingthattheassociationwassaturatedaround100mM.CLSMimagesofemulsions(HPMC/dextran)with0to300mMNaCltakenshortlyaftermixingareshowninthebottomrowofFigure8.Salt,atallconcentrationstested,hadnosignificanteffectontheaveragedropletdiameter.Themicrogelsformeddistinctlayersatthedropletsurfaces,thoughationicstrength>100mM,coverageswerenotcompleteforsomedroplets.Theaggregationofmicrogelswitheachotherandwithmicrogelsattheinterfacecanbeclearlyseenat300mM.Nevertheless,thedropletsdonotcoalesce,anddropletsaremaintainedseparatedbytheproteinclusters.TheeffectofFigure9.ThermalstabilityofHPMC/dextran(1%:12%)emulsionswith0.25%proteinmicrogelsafter30minthermaltreatmentat25,ionicstrengthondropletwasverysimilartothoseofpH4and60,and90°C.(a)Emulsionsstoredat4°Cfor0,1,and3days(from5.Therefore,wesuggestthattheaggregationrateofproteinlefttoright),(b)CLSMimagesofemulsionsshortlyafterheating,microgelsincreasesifthenetchargeofmicrogelsdecreases;and(c)CLSMimagesofheatedemulsionswiththeadditionof2mMnevertheless,thepartialinterfaciallayersonthedropletsurfaceSDSsolutions.TheemulsioniscoloredbythepresenceofFITC-actasabarrierforinhibitingdropletcoalescence.dextran(green)andrhodamineBdyedproteinmicrogels(red).5623https://doi.org/10.1021/acs.langmuir.1c00484Langmuir2021,37,5617−5626

7Langmuirpubs.acs.org/LangmuirArticleFigure10.CLSMimagesofHPMC/dextran(1%:12%)emulsionswith0.25%proteinmicrogelswiththeadditionofSDSatconcentrationsof0(control),2,4,and10mM.Blankistheoriginalemulsionwithoutanydilutionormixingtreatment.TheemulsioniscoloredbythepresenceofFITC-dextran(green)andrhodamineBdyedproteinmicrogels(red).TheFTIC-dextranconcentrationisidenticalinallsamples,buttheintensityofgreencolorwasinfluencedbystrongnegativechargesofSDS.observedaftertheheattreatment,whereastheproteinsignalinterfaceandformedsmallaggregates(reddots)inthedextranincreasedinsidetheHPMCdroplets(Figure9b),possibly(continuous)phase.ItwasobviousthatSDSfullydisruptedbecausemorehydrophobicdomainsonproteinmicrogelsweretheinteractionbetweenmicrogelsandtheHPMCphase.Thisexposedunderheating,thuspromotingtheirpartitioningtodisruptioncanbeexplainedbytwotypesofinteractionstheHPMCphase.TheeffectofSDSontheheatedemulsionbetweenproteinmicrogelsandSDS.AtpH3.0,microgelswith(Figure9c)willbediscussedinSection3.8.positivesurfacechargesareneutralizedbynegativelycharged3.7.SurfaceChargesoftheEmulsionConstituents.SDSmolecules,andproteinmicrogelstendtoaggregatewhenTobetterelucidatetheeffectofchargeonproteinpreferencetheirsurfacechargesareclosetozero.Moreover,SDSfortheinterfaceordextranphase,zetapotentialofpristinecompeteswithHPMCforinteractionswithmicrogelsthroughproteinmicrogels(0.1%)andtheirmixturewithdextranorthemergingofhydrophobicdomainsonthemicrogelsurfaceHPMCsolution(1%)weremeasured(TableS1).ThezetaandtheSDSalkyltails.Furtherincreasingtheconcentrationofpotentialsforproteinmicrogelswere21.37and−27.21mVatSDSto4and10mMresultedinthedisappearanceofthesmallpH3.0and7.0,respectively.TherewasnosignificantproteinaggregateaswellastheHPMCdroplets.Theseresultsdifferenceinthezetapotentialsofthemixturesofmicrogelareconsistentwiththosefrompreviousreports.26SDS-withdextranorHPMC,incomparisonwiththemicrogelsmicrogelsaggregatesacquirealargeamountoftotalnegativealone,thusindicatingabsentorveryweakelectrostaticcharge,whichiscapableofre-dispersingtheaggregateinwater.interactionsamongtheemulsionconstituents.AsimilarInterestingly,highconcentration(>4mM)ofSDSalsofindinghasbeenreportedbyCaminoetal.,whohavefounddisruptstheHPMCnetworkstructure,thusresultinginathatHPMCandBlgformedaweakcomplexunderacidic23lossofrheologicalcharacteristicsandtheformationofafluid-conditions.Nevertheless,owingtotheverysmalldifferences27,28likeanddilutedHPMCsolution.InthecaseofW/Wintheelectricalpotential,weconcludethattheelectrostaticemulsions,theinteractionbetweenSDSandHPMCcausestheinteractionisnotapredominantdrivingforceformicrogelincompatibleaqueousphasestobecomemiscible.accumulationontheinterface.ThemechanismofhowSDSdemulsifiesW/Wemulsions3.8.SDSEffect.ToinvestigatethehydrophobicinteractioninvolvesbothelectrostaticandhydrophobicinteractionsintheinW/Wemulsions,SDSwasaddedintotheW/WsystematpresenceoflowconcentrationsofSDS.Therefore,electrostaticpH3.SDSisusuallyusedtoinduceproteindenaturationbyandhydrophobicforcemaybothcontributetothemicrogels’bindingtothehydrophobicpatchonproteinswithitspreferencefortheinterfaceatpH3.However,theprevioushydrocarbontail.ThehydrophobicbindinghappensunderresultsshowedthattheelectrostaticinteractionsbetweenthecriticalmicelleconcentrationofSDS,whichisapprox-24microgelsandbothphaseswereweak,thusindicatingtheimately8mMinwater.Althoughthemicrogels,asaproteinhydrophobicforcepredominatedtheinteraction.structure,aresubjectedtobedestroyedbySDS,Schmittetal.25havedemonstratedthattheparticlesizeofmicrogelsisInterestingly,microgeladsorptionontheHPMCdropletsnotaffectedbySDS,thusindicatingthatthemicrogelsdonotpartiallyresistedSDSdisruptionafterbeingheatedat90°C,asdissociateintoproteinmoleculesbytheadditionofSDS.showninFigure9c.Inaddition,theheattreatmentpromotedEffectivedemulsificationofW/Wemulsionsoccurredwhenproteinmicrogelparticle−particlefusiononthesurfacesofthetheemulsionwasmixedwith2mMofSDS(datanotshown),droplets.SimilarparticlefusionhasbeenreportedforWPMon8itmaybebecausetheadditionofSDSdisruptedthethePickeringemulsionsurface.SDSdidnotdissociatethehydrophobicinteractionbetweenmicrogelsandHPMC.Asstructuresthatformedafterheating,thusindicatingthatthethephasediagramofdextran/HPMCfeaturesamiscibleone-particle−particlefusionwascausedbycovalentbindingsphaseregionunderlowpolymerconcentrations,controlbetweenmicrogelsonthesurface.Inthe90°Cheatedgroupswereconductedtoconfirmthatthedilutionbyanemulsion,thesphericalmicrogellayershrankwiththedecreaseequivalentDIwaterdidnotcausethedemulsificationoftheinthedropletsurfaceaftertheadditionofSDS(FigureS5)emulsion.andpartiallylosecontactwiththesurface.TheresultsTheeffectoftheanionicsurfactantSDSonemulsionindicatedthattheproteinmicrogelswerenot“fused”ordropletsisshowninFigure10.Withtheadditionof2mM“gelled”withtheHPMCphase,andthereforewouldnotSDS,theconfocalimagesshowedthatthemicrogelslefttheprotecttheemulsionfromdemulsification.5624https://doi.org/10.1021/acs.langmuir.1c00484Langmuir2021,37,5617−5626

8Langmuirpubs.acs.org/LangmuirArticle4.CONCLUSIONSLeiMei−DepartmentofNutrition&FoodScience,UniversityofMaryland,CollegePark,Maryland20742,UnitedStatesThestabilityoftheHPMC/dextranW/WemulsionsunderPeihuaMa−DepartmentofNutrition&FoodScience,differentenvironmentalconditionswasevaluated,andtheUniversityofMaryland,CollegePark,Maryland20742,stabilizationofemulsionswasexplainedbythebehaviorsofUnitedStatesinterfacialproteinmicrogels.TheHPMC/dextranemulsionsYuanLi−CollegeofBiosystemsEngineeringandFoodScience,werestableunderpH3−5,whereasincreasingthepHaboveZhejiangUniversity,Hangzhou310058,P.R.ChinathemicrogelpI(∼pH5)destabilizedtheemulsionbydrivingYangYuan−SchoolofChemistryandChemicalEngineering,theinterfacialadsorbedmicrogelsintothecontinuousphase.GuangzhouUniversity,Guangzhou510006,P.R.ChinaTheHPMC/dextranemulsionswerestableunderhighionicQing-ZhuZeng−SchoolofChemistryandChemicalstrengthlevels(300mM),thoughationicstrength>100mM,Engineering,GuangzhouUniversity,Guangzhou510006,thesurfaceofHPMCdropletswerenotcompletelycoveredbyP.R.Chinamicrogels.TheHPMC/dextranemulsionsstabilizedbyproteinmicrogelswerethermallystable.HeattreatmentpromotedCompletecontactinformationisavailableat:partialproteinparticle−particlefusiononthedropletsurfaceathttps://pubs.acs.org/10.1021/acs.langmuir.1c0048490°C.Moreover,ourresultsindicatedthatspecificinteractionsbetweenmicrogelsandHPMCatpH3favoredNotesthemicrogelstoentertheinterface.AdditionofSDSdisruptedTheauthorsdeclarenocompetingfinancialinterest.theinteractionbetweenmicrogelsandtheHPMCphase,leadingtomicrogelaggregationinthedextranphasethrough■theneutralizationofthepositivelychargedmicrogelsurfacesasACKNOWLEDGMENTSwellascompetingwithHPMCforhydrophobicinteractions.ThisstudyispartiallysupportedbytheU.S.DepartmentofThemicrogels’preferencefortheinterfaceatpH3wasdrivenAgriculture(USDA)HATCHfund.J.Z.thankstheUniversitybyelectrostaticandhydrophobicforces,whereasahydro-ofMarylandImagingCoreFacilityaswellasDr.YaguangLuophobicforcepredominatedtheinteraction.andDr.BinZhoufromtheUSDAfortheirtechnicalsupport.ThedatasetprovidedinthisstudyisusefulforinvestigatorswhowanttoutilizeastableW/Wemulsion.Asan■REFERENCESencapsulationsystem,anyapplicationthatcanenrichthe(1)Dickinson,E.Particle-basedstabilizationofwater-in-watercargointhedispersedphaseoftheemulsioncouldbenefitemulsionscontainingmixedbiopolymers.TrendsFoodSci.Technol.fromthissystembecauseitisstableunderahighionicstrength2019,83,31−40.andthermaltreatment.Additionally,wedemonstratedthat(2)Poortinga,A.T.Microcapsulesfromself-assembledcolloidalmicrogelparticle−particlefusionisformedonthesurfaceofparticlesusingaqueousphase-separatedpolymersolutions.LangmuirtheW/Wdropletafterthermaltreatment.Itpointstowarda2008,24,1644−1647.potentialstrategytofabricateproteinmicrocapsulesviaW/W(3)Vis,M.;Opdam,J.;van’tOor,I.S.J.;Soligno,G.;vanRoij,R.;emulsions.Tromp,R.H.;Erne,B.H.Water-in-WaterEmulsionsStabilizedbyNanoplates.ACSMacroLett.2015,4,965−968.■(4)Chatsisvili,N.;Philipse,A.P.;Loppinet,B.;Tromp,R.H.ASSOCIATEDCONTENTColloidalzeinparticlesatwater-waterinterfaces.FoodHydrocolloids*sıSupportingInformation2017,65,17−23.TheSupportingInformationisavailablefreeofchargeat(5)Singh,P.;Medronho,B.;Miguel,M.G.;Esquena,J.Onthehttps://pubs.acs.org/doi/10.1021/acs.langmuir.1c00484.encapsulationandviabilityofprobioticbacteriainediblecarbox-ymethylcellulose-gelatinwater-in-wateremulsions.FoodHydrocolloidsParticlesizedistributionofBlgmicrogelsatvariouspH2018,75,41−50.values;zetapotentialofBlgmicrogelsatvarious(6)Balakrishnan,G.;Nicolai,T.;Benyahia,L.;Durand,D.Particlesconditions;CLSMimagesofclose-upemulsiondropletsTrappedattheDropletInterfaceinWater-in-WaterEmulsions.inthepresenceofproteinmicrogels(0.5%);evolutionofLangmuir2012,28,5921−5926.HPMC/dextran(2%/12%)emulsions(pH3.0)at(7)Nguyen,B.T.;Nicolai,T.;Benyahia,L.StabilizationofWater-differentionicstrengths;CLSMimagesofheatedin-WaterEmulsionsbyAdditionofProteinParticles.Langmuir2013,HPMC/dextran(1%:12%)emulsionwith0.25%protein29,10658−10664.microgelsafter30minthermaltreatmentat90°;and(8)Sarkar,A.;Murray,B.;Holmes,M.;Ettelaie,R.;Abdalla,A.;zetapotentialofdextran(dex),HPMC,andBlgYang,X.InvitrodigestionofPickeringemulsionsstabilizedbysoftmicrogels(BM)mixturesunderdifferentpHvalueswheyproteinmicrogelparticles:influenceofthermaltreatment.SoftMatter2016,12,3558−3569.(PDF)(9)Schmitt,C.;Bovay,C.;Vuilliomenet,A.-M.;Rouvet,M.;Bovetto,L.;Barbar,R.;Sanchez,C.Multiscalecharacterizationof■AUTHORINFORMATIONindividualizedβ-lactoglobulinmicrogelsformeduponheattreatmentundernarrowpHrangeconditions.Langmuir2009,25,7899−7909.CorrespondingAuthor(10)Asenjo,J.A.;Andrews,B.A.Aqueoustwo-phasesystemsforQinWang−DepartmentofNutrition&FoodScience,proteinseparation:Aperspective.J.Chromatogr.A2011,1218,UniversityofMaryland,CollegePark,Maryland20742,8826−8835.UnitedStates;orcid.org/0000-0002-7496-3921;(11)Gonzalez-Jordan,A.;Nicolai,T.;Benyahia,L.InfluenceofthePhone:(301)405-8421;Email:wangqin@umd.eduProteinParticleMorphologyandPartitioningontheBehaviorofParticle-StabilizedWater-in-WaterEmulsions.Langmuir2016,32,Authors7189−7197.JinglinZhang−DepartmentofNutrition&FoodScience,(12)deFreitas,R.A.;Nicolai,T.;Chassenieux,C.;Benyahia,L.UniversityofMaryland,CollegePark,Maryland20742,Stabilizationofwater-in-wateremulsionsbypolysaccharide-coatedUnitedStates;orcid.org/0000-0002-5058-9488proteinparticles.Langmuir2016,32,1227−1232.5625https://doi.org/10.1021/acs.langmuir.1c00484Langmuir2021,37,5617−5626

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