AnAmericanAssociationofCerealChemists/AOACcollaborativestudywasconductedtoevaluatetheaccuracyandreliABIlityofanenzymeassaykitprocedureformeasurementoftotalstarchinarangeofcerealgrainsandproducts.Thefloursampleisincubatedat95degreesCwithThermostablealpha-amylasetocatalyzethehydrolysisofstarchtomaltodextrins,thepHoftheslurryisadjusted,andtheslurryistreatedwithahighlypurifiedamyloglucosidasetoquantitativelyhydrolyzethedextrinstoglucose.Glucoseismeasuredwithglucoseoxidase-peroxidasereagent.Thirty-twocollaboratorsweresent16homogeneoustestsamplesas8blindduplicates.Thesesamplesincludedchickenfeedpellets,whitebread,greenpeas,high-amylosemaizestarch,whitewheatflour,wheatstarch,oatbran,andspaghetti.Allsampleswereanalyzedbythestandardprocedureasdetailedabove;4samples(high-amylosemaizestarchandwheatstarch)werealsoanalyzedbyamethodthatrequiresthesamplestobecookedfirstindimethylsulfoxide(DMSO).Relativestandarddeviationsforrepeatability(RSD(r))rangedfrom2.1to3.9%,andrelativestandarddeviationsforreproducibility(RSD(R))rangedfrom2.9to5.7%.TheRSD(R)valueforhighamylosemaizestarchanalyzedbythestandard(non-DMSO)procedurewas5.7%;thevaluewasreducedto2.9%whentheDMSOprocedurewasused,andthedeterminedstarchvaluesincreasedfrom86.9to97.2%.

Enzymeactivityandpurityofthesetopics,theeasiesttodealwithistheimportanceofenzymepurityandactivity.Asascientistactivelyinvolvedinpolysaccharideresearchoverthepast25years,Ihavecometoappreciatetheimportanceofenzymepurityandspecificityinpolysaccharidemodificationandmeasurement(7).Thesefactorstranslatedirectlytodietaryfiber(DF)methodology,becausethemajorcomponentsofDFarecarbohydratepolymersandoligomers.ThecommitteereportpublishedintheMarchissueofCerealFOODSWORLDrefersonlytothemethodologyformeasuringenzymepurityandactivity(8)thatleduptheAOACmethod985.29(2).Inthisworkenzymepuritywasgaugedbythelackofhydrolysis(i.e.,completerecovery)ofaparticularDFcomponent(e.g.β-glucan,larchgalactanorcitruspectin).Enzymeactivitywasmeasuredbytheabilitytocompletelyhydrolyzerepresentativestarchandprotein(namelywheatstarchandcasein).Theserequirementsandrestrictionsonenzymepurityandactivitywereadequateatthetimethemethodwasinitiallydevelopedandservedasausefulworkingguide.However,itwasrecognizedthattherewasaneedformorestringentqualitydefinitionsandassayproceduresforenzymesusedinDFmeasurements.

Arobustandreliablemethodwasdevelopedtomeasureresistantstarch(RS),i.e.,starchthatentersthelargeintestine.InvivoconditionswerereflectedasmuchaspossIBLewhileauser-friendlyformatwasmaintained.Parametersinvestigatedincludedα-amylaseconcentration,pHofincubation,maltoseinhibitionofα-amylase,theneedforamyloglucosidaseinclusion,theeffectofshakingandstirringondeterminedvalues,andproblemsinrecoveringandanalyzingtheRS-containingpellet.TheRSvaluesobtainedwereingoodagreementwithpublishedinvivodata.Aninterlaboratoryevaluationofthemethodhasbeencompleted(FirstActionMethod2002.02).

Interlaboratoryperformancestatisticswasdeterminedforamethoddevelopedtomeasuretheresistantstarch(RS)contentofselectedplantfoodproductsandarangeofcommercialstarchsamples.FoodmaterialsexaminedcontainedRS(cookedkidneybeans,greenbanana,andcornflakes)andcommercialstarches,mostofwhichnaturallycontain,orwereprocessedtoyield,elevatedRSlevels.ThemethodevaluatedwasoptimizedtoyieldRSvaluesinagreementwiththosereportedforinvivostudies.Thirty-sevenlaboratoriestested8pairsofblindduplicatestarchorplantmaterialsampleswithRSvaluesbetween0.6(regularmaizestarch)and64%(freshweightbasis).Formatrixesexcludingregularmaizestarch,repeatabilityrelativestandarddeviation(RSD_r)valuesrangedfrom1.97to4.2%,andreproducibilityrelativestandarddeviation(RSD_R)valuesrangedfrom4.58to10.9%.Therangeofapplicabilityofthetestis2-64%RS.Themethodisnotsuitableforproductswith<1% rs="" (e.g.,="" regular="" maize="" starch;="" 0.6%="" rs).="" for="" such="" products,="">_randRSD_Rvaluesareunacceptablyhigh.

Proceduresforthemeasurementofstarch,starchdamage(gelatinisedstarch),resistantstarchandtheamylose/amylopectincontentofstarch,β-glucan,fructan,glucomannanandgalactosyl-sucroseoligosaccharides(raffinose,stachyoseandverbascose)inplantmaterial,animalfeedsandfoodsaredescribed.Mostofthesemethodshavebeensuccessfullysubjectedtointerlaboratoryevaluation.AllmethodsarebasedontheuseofenzymeseitherpurifiedbyconventionalchromatographyorproducedusingmolecularBIOLOGytechniques.Suchmethodsallowspecific,accurateandreliablequantificationofaparticularcomponent.Problemsincalculatingtheactualweightofgalactosyl-sucroseoligosaccharidesintestsamplesarediscussedindetail.

Amethodisdescribedforthemeasurementofdietaryfibre,includingresistantstarch(RS),non-digestibleoligosaccharides(NDO)andavailablecarbohydrates.Basically,thesampleisincubatedwithpancreaticα-amylaseandamyloglucosidaseunderconditionsverysimilartothosedescribedinAOACOfficialMethod2002.02(RS).Reactionisterminatedandhighmolecularweightresistantpolysaccharidesareprecipitatedfromsolutionwithalcoholandrecoveredbyfiltration.RecoveryofRS(formostRSsources)isinlinewithpublisheddatafromileostomystudies.Theaqueousethanolextractisconcentrated,desaltedandanalysedforNDObyhigh-performanceliquidchromatographybyamethodsimilartothatdescribedbyOkuma(AOACMethod2001.03),exceptthatforlogisticalreasons,D-sorbitolisusedastheinternalstandardinplaceofglycerol.Availablecarbohydrates,definedasD-glucose,D-fructose,sucrose,theD-glucosecomponentoflactose,maltodextrinsandnon-resistantstarch,aremeasuredasD-glucoseplusD-fructoseinthesampleafterhydrolysisofoligosaccharideswithamixtureofsucrase/maltaseplusβ-galactosidase.

Background:Twodistinctstarchbranchingenzyme(SBE)isoformspredatethedivergenceofmonocotsanddicotsandhavebeenconservedinplantssincethen.ThisstronglysuggeststhatbothSBEIandSBEIIprovideuniqueselectiveadvantagestoplants.However,nophenotypefortheSBEImutation,sbe1a,hadbeenpreviouslyobserved.Toexplorethisincongruitytheobjectiveofthepresentworkwastocharacterizefunctionalandmolecularphenotypesofbothsbe1aandwild-type(Wt)intheW64Amaizeinbredline.Results:Endospermstarchgranulesfromthesbe1amutantweremoreresistanttodigestionbypancreaticα-amylase,andthesbe1amutantstarchhadanalteredbranchingpatternforamylopectinandamylose.Whenkernelsweregerminated,thesbe1amutantwasassociatedwithshortercoleoptilelengthandhigherresidualstarchcontent,suggestingthatlessefficientstarchutilizationmayhaveimpairedgrowthduringgermination.Conclusions:ThepresentreportdocumentsforthefirsttimeamolecularphenotypeduetotheabsenceofSBEI,andsuggestsstronglythatitisassociatedwithalteredphysiologicalfunctionofthestarchinvivo.WebelievethattheseresultsprovideaplausiblerationalefortheconservationofSBEIinplantsinbothmonocotsanddicots,asgreaterseedlingvigorwouldprovideanimportantsurvivaladvantagewhenresourcesarelimited.

Thedietaryfibre(DF)contentinwheatgrainbasedfoodproductshavebeenestablishedwithboththeclassicalAOAC985.29dietaryfibreandthenewAOAC2009.01totaldietaryfibreprotocol.Thereisagoodagreementbetweenthehighmolecularweightdietaryfibre(HMWDF)contentsmeasuredwiththeAOAC2009.01methodand(DF)contentmeasuredwiththeclassicalAOAC985.29methodinwheatgrainbasedfoodproducts.WiththeAOAC2009.01methodalsoasignificantamountoflowmolarweightdietaryfibre(LMWDF),rangingfrom1%to3%w/w,wasmeasuredwhichisnotquantifiedwiththeAOAC985.29method.Withsemi-preparativeGPCtheLMWDF(DP≥3)fractionsinthewheatgrainbasedfoodproductswereisolated.ThemonosaccharidecompositionofthedissolvedLMWDFconstituentswasdetermined.Glucosewasbyfarthemostabundantmonosaccharidepresentwitharabinose,galactose,xyloseandmannoseasminorconstituents.ItappearedthattheLMWDFcontainsstillnotfullyconverteddigestiblestarch/malto-oligosaccharidefragmentswithDP≥3,whichareerroneouslyquantifiedasLMWDF.ByintroducinganextraAMGhydrolysisstepintheAOAC2009.01protocolafterevaporationoftheethanolanddissolvingtheresidueindeionisedwater,thesemalto-oligosaccharidesarefullyhydrolysedresultinginthatwayinacorrectandlowerLMWDFcontent.

Diabeticsarerecommendedtoeatabalanceddietcontainingnormalamountsofcarbohydrates,preferablythosewithalowglycemicindex.Forsolidfoods,thiscanbeachievedbychoosingwhole-grain,fiber-richproducts.For(sterilized)liquidproducts,suchasmealreplacers,thechoicesforcarbohydratesourcesarerestrictedduetotechnologicallimitations.Starchesusuallyhaveahighglycemicindexaftersterilizationinliquids,whereaslowglycemicsugarsandsugarreplacerscanonlybeusedinlimitedamounts.Usinganinvitrodigestionassay,weidentifiedaresistantstarch(RS)source[modifiedhighamylosestarch(mHAS)]thatmightenabletheproductionofasterilizedliquidproductwithalowglycemicindex.HeatingmHASfor4–5mininliquidincreasedtheslowlydigestiblestarch(SDS)fractionattheexpenseoftheRSportion.Theeffectwastemperaturedependentandreacheditsmaximumabove120°C.Heatingat130°CsignificantlyreducedtheRSfractionfrom49to22%.Theproductremainedstableforatleastseveralmonthswhenstoredat4°C.ToinvestigatewhetherahigherSDSfractionwouldresultinalowerpostprandialglycemicresponse,thesterilizedmHASsolutionwascomparedwithrapidlydigestiblemaltodextrin.MaleWistarratsreceivedani.g.bolusof2.0gavailablecarbohydrate/kgbodyweight.Ingestionofheat-treatedmHASresultedinasignificantattenuationofthepostprandialplasmaglucoseandinsulinresponsescomparedwithmaltodextrin.mHASappearstobeastarchsourcewhich,aftersterilizationinaliquidproduct,acquiresslow-releaseproperties.Thelong-termstabilityofmHASsolutionsindicatesthatthismayprovideasuitablecarbohydratesourceforlowglycemicindexliquidproductsforinclusioninadiabetes-specificdiet.

Anexperimentwasconductedtostudytheeffectsofinclusionofawheatcultivar(highinnonstarchpolysaccharides)andxylanasesupplementationofthedietonproductiveperformance,pHofthegastrointestinaltract,nutrientretention,andintestinalenzymeactivityofHy-LineW-36layinghensfrom25to47wkofage.Theexperimentwascompletelyrandomizedwith8treatmentsarrangedfactoriallywith4levelsofwheat(0,23,46,and69%)thatcorrespondedtoadietaryarabinoxylancontentof3.0,3.3,3.6,and3.9%,withorwithoutxylanasesupplementation.Eachtreatmentwasreplicated5times.Fortheentireexperimentalperiod,eggweight(P<0.05)=""and=""egg=""mass="">P<0.01)=""were=""reduced=""and=""the=""feed=""conversion=""ratio=""was=""hindered="">P<0.05)=""with=""increased=""levels=""of=""wheat=""in=""the=""diet,=""but=""adfi=""and=""egg=""production=""were=""not=""affected.=""xylanase=""supplementation=""improved=""egg=""production="">P<0.05),=""egg=""mass="">P<0.01),=""and=""the=""feed=""conversion=""ratio="">P<0.01).=""diet=""did=""not=""affect=""egg=""quality=""at=""any=""age,=""except=""for=""shell=""thickness=""at=""47=""wk=""that=""was=""improved=""with=""xylanase=""supplementation="">P<0.05).=""digesta=""ph=""of=""the=""different=""organs=""of=""the=""gastrointestinal=""tract=""was=""not=""affected=""by=""wheat=""inclusion=""or=""xylanase=""supplementation.=""ileal=""viscosity=""increased="">P<0.001)=""with=""wheat=""inclusion=""and=""decreased="">P<0.001)=""with=""xylanase=""supplementation=""at=""all=""ages.=""fat=""digestibility="">P<0.001)=""decreased=""with=""increased=""levels=""of=""wheat=""but="">_ncontentofthediets(P<0.05)=""and=""nitrogen=""retention=""were=""not=""affected.=""wheat=""inclusion=""increased="">P<0.001)=""amylase=""(33=""wk),=""lipase=""(33=""wk),=""and=""aminopeptidase=""(47=""wk)=""activity=""in=""the=""duodenum=""as=""well=""as=""lipase=""activity=""in=""the=""jejunum=""at=""47=""wk=""of=""age.=""however,=""xylanase=""supplementation=""did=""not=""affect=""the=""activity=""of=""any=""of=""the=""enzymes=""studied.=""it=""is=""concluded=""that=""most=""of=""the=""negative=""effects=""of=""wheat=""inclusion=""in=""the=""diet=""were=""reduced=""or=""even=""disappeared=""with=""xylanase=""supplementation.=""wheat=""with=""a=""high=""nonstarch=""polysaccharide=""content=""(pishtaz=""cultivar)=""can=""be=""used=""at=""levels=""of=""up=""to=""69%=""in=""laying-hen=""diets=""without=""negatively=""affecting=""bird=""performance,=""provided=""that=""feeds=""are=""supplemented=""with=""xylanase.="">

Tenparentcornlines,includingfourmutants(dullsugary2,amylose-extendersugary2,amylose-extenderdull,andanamylose-extenderwithintrogressedGuatemalengermplasm[GUATae])andsixlineswithintrogressedexoticgermplasmbackgrounds,werecrossedwitheachothertocreate20Progenycrossestoincreaseresistantstarch(RS)asadietaryfiberincornstarchandtoprovidematerialsforthermalevaluation.Theresistantstarch2(RS2)valuesfromthe10parentlineswere18.3–52.2%andthevaluesfromthe20progenycrosseswere16.6–34.0%.The%RS2ofparentswasnotadditiveintheoffspringbutgreaterRS2inparentswascorrelatedtogreaterRS2intheprogenycrosses(r=0.63).Differentialscanningcalorimetry(DSC)measuredstarchthermalcharacteristics,revealingpositivecorrelationsofpeakgelatinizationtemperatureandchangeinenthalpywith%RS2(r=0.65andr=0.67,P≤0.05);however,%retrogradation(ameasureofRS3)andretrogradationparametersdidnotcorrelatewith%RS2.The%RS2andonsettemperatureincreasedwiththeadditionoftheaegene,likelybecauseRSdelaysgelatinization.

Pastrywheatflourwasextrudedundervariousconditionsoffeedmoisture(20%,40%,and60%)andscrewspeed(150,200,and250rpm),atconstantbarreltemperatureprofile(40,60,80,100,and120°C,feedporttoexitdie).Theextrudedsampleswerestoredat4°Cfor0,7,or14days,atwhichtimesresistantstarch(RS)formationwasanalyzed.Thermalandpastingpropertiesofextrudedsamplesstoredfor14dayswereanalyzedusingadifferentialscanningcalorimeterandrapidviscoanalyzer(RVA),respectively.TheRScontentincreasedafterextrusioncomparedtonon-extrudedpastrywheatflour.Highsignificantpositivecorrelationsoffeedmoisture(P<0.01)=""and=""storage=""period="">P<0.05)=""with=""rs=""formation=""were=""observed.=""the=""rs=""derived=""from=""extrusion=""and=""storage=""showed=""higher=""thermal=""stability=""with=""decreasing=""feed=""moisture=""and=""screw=""speed.=""statistically=""significant=""differences=""in=""pasting=""properties=""were=""observed=""with=""feed=""moisture=""or=""screw=""speed.=""in=""particular,=""the=""setback=""value=""from=""rva=""of=""the=""sample=""was=""significantly=""increased=""with=""increasing=""feed=""moisture.=""these=""results=""indicate=""that=""feed=""moisture=""and=""storage=""time=""were=""both=""important=""factors=""for=""the=""formation=""of=""rs=""from=""pastry=""wheat=""flour=""during=""extrusion.="">

Thebreadwheat(TriticumaestivumL.)analysedinthisstudyhasbeenproducedbygeneticallyeliminatingthestarchsynthaseIIaandshowsapparenthighamylose(HA)intheflourstarch.SomestarchpropertiesoftheHAwheatwereanalysed.TheHAwheatcontained2.8–3.6%resistantstarch(RS),muchmorethanthenormal(control)wheat,whichcontainedalmostnoRS.AutoclavingtheHAandnormalwheatstarchesincreasedRS.Theformercontained10.5%RSandthelatter5.9or6.8%RS.SwellingoftheHAwheatstarchanditspastingpropertiesusingRapidViscoAnalyzer(RVA)wereinvestigated.Swellingpower(g/g)oftheHAwheatin0.1%AgNO₃andswellingvolume(mL/g)inureasolutionweresignificantlylessthanthoseofthenormalwheat.TheRVAprofileoftheHAwholemealandstarchalsodifferedfromthenormal.Thepeakviscosity,minimumviscosity,andfinalviscosityofHAwerelow,andbreakdown(peakminusminimumviscosity)wasverysmall.ThesefindingsshowthatamountofresistantstarchandpastingpropertiesareuniqueintheHAwheatstarch,probablycausedbylackofstarchsynthaseIIa.

Extrusioncookingiscommonlyusedintheproductionofsnacks.Inthepresentstudy,extrudateswerepreparedusingbarleyflouraloneandwiththeadditionofeitherpolydextrose(PD)orwheyproteinisolate(WPI)andbothPDandWPI.Independentprocessvariableswerewatercontentofthemass(17%,20%and23%),screwspeed(200,350and500rpm)andtemperatureofsection6anddie(110,130and150°C).Expansion,hardness,watercontent,porosityandchemicalcompositionoftheextrudateswereanalysed.HighlyporousandexpandedsnackproductswithhighdietaryfibreandproteincontentswereobtainedfrombarleyflourandWPIwhenwatercontentofmasswas17%,screwspeed500rpmandtemperatureofsection6anddie130°C.BarleyflouraloneorwithPDresultedinhardandnon-expandedextrudates.Expansionofextrudateswasstatisticallysignificantlyincreasedwithdecreasingwatercontentofthemassandincreasingscrewspeedinalltrials.

IntroductionThepresenceofresistantstarchinsamplescontainingnon-starchpolysaccharideshasalwaysbeenachallengetoenzymatictotalstarchandtotalfibreanalysis.ObjectiveandmethodsBasedonmicrowave-inducedpressuredisintegrationtechniquetheAssociationofOfficialAnalyticalChemistsmethodsforthedeterminationoftotalstarch(AOAC996.11)andtotaldietaryfibre(AOAC991.43)havebeenmodifiedtocompletelyeliminateundesirableresistantstarchfractionswithrespecttodigestionproceduresusingthermostableα-amylaseandamyloglucosidase.ResultsMicrowavetreatmentofhigh-amylosestarchsamplesresultedinexcellenttotalstarchrecoveryintheAssociationofOfficialAnalyticalChemistsstandardmethodno.996.11.AfterintegrationofmicrowavedisintegrationtechniqueintothetotaldietaryfibremethodAOAC911.43irradiationexperimentswithdifferentmodelmixturesconsistingofnon-starchpolysaccharidescomponentsandhigh-amylosestarchfractionsresultedinthecompleteeliminationofundesirableresistantstarchfractions.ConclusionThereforethemicrowavetechniquecanbeaveryefficientmeansfortheeliminationofresistantstarchandprovidesmorerealisticvaluesinanalyticaltotaldietaryfibreprocedureswithrespecttosamplescontainingcriticalenzymeresistantstarches.

ResistantStarch(RS)isatypeofstarchthatisresistanttostarchhydrolyzingenzymesinthestomachandthusbehavesmorelikedietaryfibre.RShasbeenshowntohavebeneficialeffectsindiseasepreventionincludingmodulationofglycaemicindexdiabetes,cholesterolloweringcapabilityandweightmanagement,whicharecriticallyimportantformanypeopleintheFederatedStatesofMicronesia.GreenbananasareknowntocontainsubstantialconcentrationsofRSandareacommonpartoftheMicronesiandiet.ThereforetheaimofthisstudywastodeterminetheRScontentinbananacultivarsfromPohnpei,Micronesia:Daiwang,Inahsio,Karat,UtinKerenisandUtinRuk,forwhichnosuchinformationwasavailable.UtinKerenis,InahsioandUtinRukwerefoundtocontainthehighestamountsofRS.ThefateofRSafterincorporationintoafoodproduct(i.e..pancakes)wasalsostudiedandasignificantreductionintheRScontentwasfoundforeachcultivaraftercooking.Microscopyofthebananasamplesindicatedthattheoverallmorphologyofthecultivarswassimilar.Inconclusion,greenbanana,includingthesevarieties,shouldbepromotedinMicronesiaandotherplacesfortheirrichRScontentandrelatedhealthbenefitsincludingdiabetescontrol.FurtherresearchisneededtomoreclearlydeterminetheeffectsofcookingandfoodprocessingonRS.

TypeIIIresistantstarch(RS)isunderstoodtobeduetotheorderedstructureformationintheprocessofretrogradation.Mosttreatmentsofgranularhigh-amylosemaizestarch(HAMS)donotcompletelyeliminatetheoriginalorderedstructure.WehypothesizedthatresidualorderedstructurewouldconstrainsubsequentphysicalreassociationofchainsandtheformationofRS.Theobjectivewastogeneratedifferencesinenzymesusceptibilityusingtwomeansofprecipitationoffullydispersedstarchandtorelatedifferencesinenzymesusceptibilitytothestructureoftheprecipitates.Dispersionsinsodiumhydroxidewereprecipitatedeitherwithethanolorammoniumsulfate.RSandthetimecourseofdigestionweredetermined.Crystallinityandhelicitywereestimatedusingwide-angleX-raydiffractionandsolid-state¹³CCP/MASNMR,respectively.PrecipitationofwholestarchwithethanolledtolowerRSvalues(≈24%)thanprecipitationwithammoniumsulfate(≈39%)andalsotohigherreactionrateconstantsforanearlycomponentofdigestion.EthanolprecipitationofabranchedstarchfractiongaveessentiallynoRS,whereasammoniumsulfateprecipitationofthesamebranchedmaterialhad>20%RS.Ethanolprecipitatescontainedsinglehelices,inmostbutnotallcases,contributingtoV-typecrystallinity.AmmoniumsulfateprecipitateshaddoublehelicescontributingtoB-typecrystallinity.

Thefermentationpotentialofspentturmericwasstudiedininvitroswinefaecalbatchcultures.Thespentturmericresidue(theenzyme-resistantfractionfromspentturmeric,EST)wasobtainedthroughtheuseofthedigestiveenzymesamyloglucosidaseandpancreatinandcomparedtocelluloseandhigh-amylosestarch(HAS)ascarbonsources.ESTshowedsignificantincreasesintotalanaerobes,bifidobacteria,lactobacilliandlacticacidbacteriapopulationscomparedtocelluloseat12,24and48h,andthetotalanaerobiclevelintheHASgroupwassignificantlyhigherthaninthecellulosegroupat24and48h.However,asignificantdecreaseinthecoliformpopulationwasonlyfoundintheHASgroupcomparedtothecellulosegroupat48h.Thetotalshort-chainfattyacid(SCFA)concentrationsintheESTandHASgroupsweresignificantlyhigherthanthatinthecellulosegroupat12hand48h.However,therewasnosignificantdifferenceinthetotalSCFAconcentrationbetweentheESTandHASgroupsat12hand48h.AmmoniaandpHlevelsintheESTandHASgroupsweresignificantlylowerthanthoseinthecellulosegroupat24and48h,buttherewasnosignificantdifferencebetweentheESTandHASgroups.Theseresultsindicatethatthefermentationpotentialoftheenzyme-resistantfractionfromspentturmericiscomparabletothatofcommerciallyestablishedresistantstarch.

Wheatflourreplacementfrom22.5%upto45%byincorporationofternaryblendsofteff(T),greenpea(GP)andbuckwheat(BW)floursprovidedtechnologicallyviableandacceptablesensoryratedmultigrainbreadswithsuperiornutritionalvaluecomparedtothe100%wheatflour(WT)counterparts.Blendedbreadsexhibitedsuperiornutritionalcomposition,largeramountsofbioaccessiblepolyphenols,higheranti-radicalactivity,andlowerandslowerstarchdigestibility.Simultaneouslowerrapidlydigestiblestarch(57.1%)andhigherslowlydigestiblestarch(12.9%)andresistantstarch(2.8%)contents(gper100gfreshbread),consideredsuitablenutritionaltrendsfordietarystarchfractions,weremetbytheblendformulated7.5%T,15%GP,15%BK.Theassociatedmixturethatreplaced37.5%WT,showedaratherlowerextentandslowerrateofstarchhydrolysiswithmedium-lowvaluesforC_∞,andH₉₀,andlowestk,andintermediateexpectedGlycaemicIndex(86).Allmultigrainbreadscanbelabelledassourceofdietaryfibre(≥3gdietaryfibre/100gbread).

Purplesweetpotatostarchisapotentialresourceforresistantstarchproduction.Theeffectsofheat-moisturetreatment(HMT)andenzymedebranchingcombinedheat-moisturetreatment(EHMT)onthemorphological,crystallinityandthermalpropertiesofPSPstarcheswereinvestigated.Theresultsindicatedthat,afterHMTorEHMTtreatments,nativestarchgranuleswithsmoothsurfacewasdestroyedtoformamorecompact,irregularandsheet-likestructure.ThecrystallinepatternwastransformedfromC-typetoB-typewithdecreasingrelativecrystallinity.Duetostrongercrystallitesformedinmodifiedstarches,theswellingpowerandsolubilityofHMTandEHMTstarchweredecreased,whilethetransitiontemperaturesandgelatinizationenthalpyweresignificantlyincreased.Inaddition,HMTandEHMTexhibitedgreatereffectsontheproliferationofbifidobacteriacomparedwitheitherglucoseorhighamylosemaizestarch.

Thepresentstudyinvestigatedmetabolomicandtranscriptomicresponsesintheliversofpigstoevaluatetheeffectsofresistantstarchonthebody’smetabolismattheextraintestinallevel.Thirty-sixDuroc×Landrace×LargeWhitegrowingbarrows(70dofage)wererandomlyallocatedtoeitherthecornstarch(CS)grouportherawpotatostarch(RPS)groupwitharandomizedcompleteblockdesign;eachgroupconsistedof6replicates(pens),with3pigsperpen.PigsintheCSgroupwereofferedacorn–soybean–baseddiet,whereaspigsintheRPSgroupwereputonadietinwhich230(growing)or280g/kg(finishing)purifiedCSwasreplacedwithpurifiedRPSduringa100-dtrial.Theliversofpigswerecollectedformetabolomeandgeneexpressionanalysis.Gaschromatography–massspectrometryanalysisshowedthatcomparedwiththeCSdiet,theRPSdietdecreased(P<0.05)=""cholesterol=""and=""palmitic=""acid=""as=""well=""as=""increased="">P<0.05)=""3-hydroxybutyric=""acid,=""which=""indicated=""the=""reduction=""of=""adipose=""weight=""and=""fatty=""acid=""biosynthesis=""and=""the=""elevation=""of=""fatty=""acid=""β-oxidation.=""in=""addition,=""2-ketoglutaric=""acid=""and=""glucose-6-phosphate=""were=""increased="">P<0.05)=""although=""pyruvic=""acid=""was=""decreased="">P<0.05)=""in=""the=""rps=""group,=""indicating=""the=""upregulated=""capacity=""of=""glucose=""phosphorylation=""and=""glycolysis.=""microarray=""analysis=""showed=""that=""the=""mrna=""expression=""of="">transmembraneglycoproteinclusterofdifferentiation36(CD36),carnitinepalmitoyltransferase1B(CPT1B),andmedium-chainacyl-CoAdehydrogenase(ACADM)weredownregulated(P<0.05)=""whereas="">1-acylglycerol-3-phosphateO-acyltransferase4(AGPAT4),glycerol-3-phosphateacyltransferase(GPAT),andfattyacidbindingprotein1(FABP1)wereupregulated(P<0.05)=""in=""the=""rps=""diet,=""indicating=""a=""decrease=""in=""fatty=""acid=""intake=""and=""synthesis=""and=""an=""increase=""in=""fatty=""acid=""oxidation=""and=""glycerophospholipid=""synthesis.=""the=""results=""demonstrated=""that=""the=""long-term=""consumption=""of=""rps=""could=""modulate=""hepatic=""lipid=""metabolism=""by=""decreasing=""fatty=""acid=""synthesis=""as=""well=""as=""increasing=""lipid=""oxidation=""and=""glycerophospholipid=""synthesis.="">