Megazyme/βGlucan (Oat; Medium Viscosity)/PBGOM/5 grams

Fermentationofβ-glucanfractionsfrombarley[averagemolecularmass(MM),of243,172,and137kDa]andoats(averageMMof230and150kDa)bythehumanfaecalmicrobiotawasinvestigated.FractionsweresupplementedtopH-controlledanaerobicbatchculturefermentersinoculatedwithhumanfaecalsamplesfromthreedonors,intriplicate,foreachsubstrate.Microbiotachangesweremonitoredbyfluorescentinsituhybridization;groupsenumeratedwere:Bifidobacteriumgenus,BacteroidesandPrevotellagroup,Clostridiumhistolyticumsubgroup,Ruminococcus-Eubacterium-Clostridium(REC)cluster,Lactobacillus-Enterococcusgroup,Atopobiumcluster,andclostridialclusterIX.Short-chainfattyacidsandlacticacidweremeasuredbyHPLC.TheC.histolyticumsubgroupincreasedsignificantlyinallvesselsandclostridialclusterIXmaintainedhighpopulationswithallfractions.TheBacteroides-Prevotellagroupincreasedwithallbutthe243-kDabarleyand230-kDaoatsubstrates.Ingeneralβ-glucansdisplayednoapparentprebioticpotential.TheSCFAprofile(51:32:17;acetate:propionate:butyrate)wasconsideredpropionate-rich.Inafurtherstudyaβ-glucanoligosaccharidefractionwasproducedwithadegreeofpolymerizationof3-4.Thisfractionwassupplementedtosmall-scalefaecalbatchculturesandgavesignificantincreasesintheLactobacillus-Enterococcusgroup;however,theprebioticpotentialofthisfractionwasmarginalcomparedwiththatofinulin.

Objective.Antimicrobialpeptidesandtightjunctionproteinsarecrucialtomaintainmucosalimmunity.Itisknownthatoatβ-glucanmayaffectintestinalimmunity.Therefore,theaimofthepresentstudywastoevaluatetheeffectofoatβ-glucanonthepresenceofantimicrobialpeptidesandtightjunctionprotein.Materialandmethods.Weanalyzedantimicrobialpeptidelevelsinfecalwaterpreparedfrom24hileostomicbagcontentsobtainedfromileostomicpatientsconsumingoatβ-glucanenrichedorcontroldietsinacross-overdesign.Inaddition,intestinalsectionsofmice,whichreceivedoatβ-glucanviaoralgavagesfor3.5days,wereanalyzedforlysozymeandzonulaoccludens-1expression.Results.Weobservedatrendtowardlowerlysozyme(−23%;p=0.076)andbactericidal/permeABIlity-increasingprotein(−17%;p=0.098)levelsinoatβ-glucanenrichedfecalwaterascomparedwithplacebo.Additionally,micereceivingoatβ-glucanshowedalowerlysozymeexpressioninstaineddistalsmallintestinalsections(p=0.011).Stainingofzonulaoccludens-1wasdecreasedinβ-glucantreatedmiceindicatingdisruptionofthetightjunctionintegrity.Conclusions.Inconclusion,theconsumptionofoatβ-glucanseemstodecreasethelevelsofantimicrobialpeptidesinfecalwaterfromhumanileostomypatientsanditsexpressionindistalsmallintestinesectionsinmice.Thedecreasedintestinalintegrityinmicecouldbeexplainedbythedropinantimicrobialpeptides.

Dietaryfibers(oatβ-glucan,flaxseedgum,andfenugreekgum)canbefermentedtoshortchainfattyacids(SCFAs)inbatchculturesbypigintestinaldigesta.Lactateintheβ-glucan-growncultureshadthehighestlevelamongSCFAsproduced,whereasflaxseedorfenugreekgum-containingculturesgeneratedasignificantamountofacetate,propionateandbutyrateoverthreesubculturestested(p<0.05).=""denaturing=""gradient=""gel=""electrophoresis=""(dgge)=""analysis=""of=""16s=""rrna=""genes=""in=""the=""initial=""and=""subcultures=""revealed=""that=""types=""of=""fibers=""impacted=""pronouncedly=""on=""the=""bacterial=""community=""structure.=""identified=""dgge=""dna=""bands=""were=""mainly=""affiliated=""with="">Bacteroidetes,andFirmicutes,inwhichnumbersofbutyrate-producingspecieswerewidelydistributed.ThefermentabilityofdietaryfiberstoSCFAsandtheirselectiontowardsthebacterialcommunitiessuggesttheirpotentialapplicationinpromotinganimal/humanhealth.

Β-glucanisoneofthecomponentsthatdifferentiateoatsfromothercerealsandthatcontributetothehealth-relatedvalueofoats.However,sofaroatscannoteasilybeappliedinbread-likeproductswithoutlossofproductquality.Herewehavestudiedhowthecontentandviscosityofoatβ-glucanaffectthetechnologicalpropertiesofoatdoughinbothagluten-freeandagluten-containingsystem.Inbothsystems,increasingtheβ-glucanconcentrationresultedinanincreaseofdoughstiffnessandinareductionofdoughextensibility.β-glucannegativelyimpactedtheelasticpropertiesthatadditionalwheatglutenconferredtooatdough.Thiseffectwassmallerformedium-viscosityβ-glucanthanforhigh-viscosityβ-glucan.Interestingly,doughmadefromlowβ-glucanflour(<2%) had="" increased="" gas="" retention="" capacity.="" overall,="" the="" impact="" of="" β-glucan="" on="" the="" properties="" of="" oat="" dough="" systems="" was="" governed="" by="" concentration="" and="" viscosity,="" with="" or="" without="" additional="" wheat="" gluten.="" our="" findings="" indicate="" that="" β-glucan="" is="" a="" key="" component="" that="" determines="" the="" rheology="" of="" oat-based="" dough="" systems="" and,="" with="" that,="" the="" technological="" functionality="" of="" oat="" in="" dough="" systems.="">

Oatβ-Glucanswerestudiedfortheirimmunologicalimpactbeforeandafterenzymaticdigestioninordertoenhancetheefficacyofoatβ-Glucansforapplicationinfunctionalfoods.Oatβ-Glucanisreportedtohaveminimalimpactcomparedtoitsfungalcounterpartinvitro.Digestionwithendo-glucanaseenhanceditsefficacytowardsstimulatingMCP-1,RANTES,IL-8,andIL-4productioninhumandendriticcellsascomparedtothenondigestedβ-Glucan.ThiseffectresultedfromanenhancedactivationoftheDectin-1receptor.Ourdatasuggestthattheimmune-stimulationwasdependentontheβ-(1-3)linkagesandthereducedparticlesizeofdigestedβ-Glucans.Thus,weshowthatenzymaticpre-digestionofdietaryfibressuchasoatβ-Glucanenhancesitsimpactonspecificimmunereceptors.Wealsodemonstratethatparticlesizeand/ormolecularweightofoatβ-Glucansandexposureofspecificbindingsitesforthereceptorsmightbeimportanttoolsfordesigningefficaciousfunctionalfeedandfoodadditives.