Aprocedurepreviouslydevelopedfortheassayofcereal-flourβ-amylasehasbeenimprovedandstandardised.Theimprovedprocedureusesthesubstratep-nitrophenylmaltopentaose(PNPG5)inthepresenceofnearsaturatinglevelsofα-glucosidase.PNPG5israpidlyhydrolysedbyβ-amylasebutlessreADIlybycerealα-amylases.Thesubstrateishydrolysedbyβ-amylasetomaltoseandp-nitrophenylmaltotriose(PNPG3).Withthelevelsofα-glucosidaseusedinthesubstratemixture,PNPG3israpidlycleavedtoglucoseandp-nitrophenol,whereasPNPG5isresistanttohydrolysisbytheα-glucosidase.Theassayprocedurehasbeenstandardisedforseveralβ-amylasesandtheexactdegreeofinterferencebycerealα-amylasesdetermined.Theprocedurecanbereadilyappliedtotheselectivemeasurementofβ-amylaseactivityincerealandmaltedcereal-flours.

Steepingindilutealkaline(0.2%NaOH)followedbyresteepinginbiocontrol(startersofBacillussubtilisS499)hasbeenusedduringredsorghummalting.Theeffectofsteepingandgerminationconditionshasbeendescribedusing2functions:aWeibull4-parametermodelcombinedwithaGeneralLinearModelwithLogarithmLinkwithsignificantgoodness.Steepingconditions(combineduseofNaOHandB.subtilisS499)affectsthesynthesiscapacityofgrain:whenB.subtiliscultureusedinthesteepingstepisdiluted,lnαincreases,suggestingalossoftreatmentefficacy.Thegerminationtemperatureaffectstheβ-amylasesynthesisrateduringtheinductionphase:thegerminationtemperatureincreaseisaccompaniedbyadecreaseoftheβ-amylasesynthesisrate.Duringtherepressionphaseofβ-amylasesynthesis,theeffectofmaltingconditionswasfoundtotaper.

Predictionofmaltfermentability(apparentattenuationlimit—AAL)bymeasurementofthediastaticpowerenzymes(DPE),α-amylase,totallimitdextrinase,totalβ-amylase,β-amylasethermostability,andtheKolbachindex(KIorfreeaminonitrogen—FAN)issuperiortotheconventionaluseofdiastaticpower(DP)alone.Thethermostabilityofβ-amylaseisknowntobeanimportantfactorindeterminingfermentability,thusthethermostabilityoftheotherrelativelythermolabileenzyme,limitdextrinase,wasinvestigatedtodetermineifitwasalsousefulinpredictingfermentability.Tofacilitatethisaim,methodsweredevelopedforarapidandcostefficientassayofbothβ-amylaseandlimitdextrinasethermostability.InternationallyimportantAustralianandinternationalmaltingvarietieswerecomparedfortheirtotallimitdextrinaseandβ-amylaseactivityandthermostability.Interestingly,theleveloflimitdextrinasethermostabilitywasobservedtobeinverselycorrelatedwithtotallimitdextrinaseactivity.Thepredictionofmaltfermentabilitywasachievedbybothforwardstep-wisemulti-linearregression(MLR)andthepartialleastsquares(PLS)multivariatemodeldevelopmentmethods.Bothmethodsproducedsimilaridentificationsoftheparameterspredictingwortfermentabilityatsimilarlevelsofpredictivepower.BothmodelsweresubstantiallybetteratpredictingfermentabilitythanthetraditionaluseofDPonitsown.Theemphasisofthisstudywasontheidentificationofpredictivefactorsthatcanbeconsistentlyusedinmodelstopredictfermentability,becausethemodelparameterestimateswillsubtlyvarydependingonmashingconditions,yeaststrain/fermentationconditionsandmaltsource.Theapplicationofthesemultivariatemodeldevelopmentmethods(PLSandMLR)enabledtheidentificationoffurtherpotentialfermentabilitypredictingfactors.TheanalysesdividedthepredictiveparametersintothosedefinedbyDPenzymesandthoseassociatedwithmodification(KI,FAN,fine/coarsedifference,wortβ-glucanandfriability).Surprisingly,limitdextrinasethermostabilitywasnotasubstantialpredictoroffermentability,presumablyduetoitsnegativecorrelationwithtotallimitdextrinaseactivity.Theapplicationoftheseinsightsinthemaltingandbrewingindustriesisexpectedtoresultinsubstantialimprovementsinbrewingconsistencyandenablemorespecificqualitytargetsforbarleybreeder"sProgenyselectioncut-offlimitstobemorepreciselydefined.

Maltedandun-maltedsorghum(Sorghumbicolor(L.)Moench)flourwasgammairradiatedwithadoseof10kGyandthenre-irradiatedwith25kGy.Theeffectsofirradiationonmicrobialdecontamination,amylaseactivity,fermentability(usinganamylolyticL.plantarumMNC21strain),starchgranulestructureandviscosityweredetermined.Standardmethodswereusedduringdeterminations.The10kGydosehadnoeffectonmicrobialloadofun-maltedflourbutreducedthatofmaltedflourby3logcycles.Re-irradiationresultedincompletedecontamination.Irradiationofmaltcausedasignificant(p<0.05) reduction="" in="" alpha="" and="" beta="" amylase="" activity="" (22%="" and="" 32%,="" respectively).="" irradiation="" of="" un-malted="" flour="" increased="" the="" rates="" of="" utilization="" of="" glucose="" and="" maltose="" by="" 53%="" and="" 100%,="" respectively,="" during="" fermentation.="" however,="" microbial="" growth,="" rate="" of="" lactic="" acid="" production,="" final="" lactic="" acid="" concentration="" and="" ph="" were="" not="" affected.="" starch="" granules="" appeared="" normal="" externally="" even="" after="" re-irradiation,="" however,="" granules="" ruptured="" and="" dissolved="" easily="" after="" hydration="" and="" gelatinization.="" production="" of="" high="" dry="" matter="" density="" porridge="" (200="" g="" dry="" matter/l)="" with="" a="" viscosity="" of="" 3500="" cp="" was="" achieved="" by="" irradiation="" of="" un-malted="" flout="" at="" 10="" kgy.="" gamma="" irradiation="" can="" be="" used="" to="" decontaminate="" flours="" and="" could="" be="" utilized="" to="" produce="" weaning="" porridge="" from="" sorghum.="">

Enzymaticactivityoftenreducesthenutritionalvalueofwheatflourduringfoodmanufacturing,causingcompounddegradationand/orheatdamage.Thechoiceofwheatvarietieswithlowenzymaticactivitycouldthereforehelptopreservethenutritionalqualityoffood.Theaimofthisresearchwastoevaluatepolyphenoloxidase,alpha-amylaseandbeta-amylaseactivitiesinwholemealfloursof59accessionsbelongingtodifferentwheatspeciesandsubspecies,croppedintwoyears.TheextractionpH(7.0),reactionpH(5.5)andreactiontemperature(45°C)weredeterminedbypreliminarytrials.TheANOVAhighlightedsignificantdifferencesforallenzymesamongspecies/subspeciesand,foramylases,betweencroppingyears;however,theyearinfluencewasoverwhelmingonlyforalpha-amylase.Einkornshowedthehighestpolyphenoloxidase(362.1±9.46U/gDM)aswellasthelowestalpha-amylase(0.20±0.006CU/gDM)andbeta-amylase(12.0±0.36B3U/gDM)activities.Theembryo/scutellumhadthehighestpolyphenoloxidaseandalpha-amylasevalues,followedbythebranandtheendosperm;incontrast,beta-amylasewasevenlydistributedinthebranandtheendosperm,andwasabsentintheembryo/scutellum.

Tolimitnutritionallossesandoptimisebreadprocessing,heatdamageindices(furosine,glucosylisomaltol,hydroxymethylfurfural),sugars,α-amylase,β-amylaseandcolourweremonitoredduringbreadmanufacturingfromrefinedflourofthreeeinkorn,threebreadandonedurumwheatsamples.Theheatdamageindicesincreasedonlyduringthebakingstep.Furosinewassignificantlylowerineinkorn(onaverage,9.3±5.33and25.3±10.70mg/100gproteinincrumbandcrust,respectively)thaninbreadwheat(31.6±3.05and115.6±13.53)anddurumwheat(36.2±2.82and165.0±3.17).Glucosylisomaltolandhydroxymethylfurfuralweredetectedonlyinthecrust,withlowerlevelsineinkorn(onaverage,2.3±1.78and10.0±7.79mg/kgDM,respectively)thaninbreadwheat(13.1±5.57and42.8±10.64)anddurumwheat(18.9±1.11and57.2±0.80).Thedifferentbehaviourofeinkornwasprobablyrelatedtoitsmoderateβ-amylaseactivity,andthusthelowmaltosecontentofitsdough.Colourwascorrelatedwithheatdamage,aseinkornbreadswerelighterthantheothers.Theresultsshowthateinkornbreadundergoeslowerheatdamagethananalogousproductsfromdurumandbreadwheat,thusprobablybetterpreservingitsnutritionalvalue.

Barleymaltisthepreferredbrewingmaterialthesedaysbecauseofitshighextractcontentandhighenzymeactivities.However,whensubstitutingmaltedbarleywithoatstocreateauniquebeerflavorandaroma,endogenousmaltenzymesbecomethelimitingfactor.Therefore,theobjectivesofthisstudyweretoevaluatetheeffectof10–40%unmaltedoatsonthequalityofhigh-gravitymashes/wortsandtoinvestigatethelimitationsofendogenousmaltenzymesaswellasthebenefitsoftheapplicationofindustrialenzymes.TheenzymemixOndea®Prowasfoundtobeparticularlysuitableformashingwithunmaltedoatsandwasthereforeusedinthepresentrheologicaltestsandlaboratory-scalemashingtrials.Inordertogaindetailedinformationaboutthebiochemicalprocessesoccurringduringmashing,thequalityofmasheswascomprehensivelyanalyzedaftereachmashrestusingstandardmethodsdescribedbyMitteleuropäischeBrautechnischeAnalysenkommissionandLab-on-a-Chipcapillaryelectrophoresis.Mashingwithupto40%oatsresultedinincreasedmashconsistencies,color/pH(20°C)values,β-glucanconcentrations,wortviscosities12.0%,andfiltrationtimesaswellasdecreasedFANandextractcontents.TheapplicationofOndea®ProenormouslyincreasedthecolorofwortsdespitelowerpHvaluesbutconsiderablyimprovedthequalityandprocessabilityof30or40%oat-containingmashes/worts.However,thesubstitutionofupto20%barleymaltwithunmaltedoatscaneasilyberealizedwithouttheadditionofexogenousenzymes.

Brewingwithcommercialflourshasthepotentialtoreducemashingtimesandimprovebrewhouseefficiency.Atpresent,however,nostudiesareavailableassessingtheapplicationofcommercialoatandsorghumfloursasbrewingadjuncts.Therefore,theobjectivesofthisstudyweretoevaluatethequalityandprocessabilityofmashes/wortsproducedwith10–90%oatorsorghumflouraswellastorevealtheadvantagesandlimitationsoftheiruseasasubstituteforbarleymalt.Forthesepurposes,bothflourtypeswerefullyanalyzedintermsofbrewing-relevantcharacteristicsusingstandardmethods,Lab-on-a-Chipcapillaryelectrophoresis,andscanningelectronmicroscopy.Laboratory-scalemashingtrialswereperformedtoassesstheeffectofupto90%flouradjunctonmash/wortquality.Equivalentfactorswereintroducedtodeterminetheperformanceefficiencyofdifferentoat/sorghumflourconcentrations.CommercialoatfloursourcedinIrelandexhibitedsignificantlymoreprotein,β-glucan,andfat,lessstarch,ash,andpolyphenols,aswellasalowerstarchgelatinizationtemperaturethancommercialsorghumflourobtainedfromtheUSA.Wortsproducedwith10–90%oatorsorghumflourhadlightercolors,higherpHvalues,andlowerconcentrationsoffoam-positiveproteinsaswellasfreeaminonitrogencomparedto100%barleymaltworts.Intermsofextractyields,theuseofupto70%oatflourand50%sorghumflour,respectively,hasproveneconomicallybeneficial.Wortscontainingupto70%oatflourshowedaverygoodorgoodfermentability,thosecontaining30–50%sorghumflourresulted,however,inaloweralcoholproduction.

Oatmaltisanutritionallyrichingredientmainlyusedinasmallnumberofspecialityproducts.Theaimofthisstudywastoevaluatethesuitabilityofoatmaltinwheatbaking.Theeffectofoatmaltonbreadanddoughpropertiesatlevelsrangingfrom0.5%to5%wasstudiedandcomparedwithbarleyandwheatmalts.Theadditionofallmaltsincreasedloafspecificvolumes.Barleyandwheatmaltsatlevelsabove2.5%ledtoastickyandcoarsecrumb,buttheeffectofoatmaltonthecrumbgrainwasnegligIBLe.Rheologicalcharacterisationcouldnotexplainthesuperiorbakingperformanceofoatmalt,asitincreasedextensibilityanddecreasedresistanceextensivelyindicatingweakeningoftheextensionalpropertiesoftheglutennetwork.Thehighlipolyticactivitymayhavecompensatedforthelossofdoughstrengthbyimprovingthesurfacepropertiesofgascells.Theresultsshowthatoatmaltcanbeusedinwheatbakingtoimprovetheloafvolumeandnutritionalqualitywithoutthedetrimentaleffectsassociatedwiththeexcessamylolyticactivityofbarleyandwheatmalts.

Tolimitheatdamageandimprovethenutritionalpropertiesofbakeryproducts,furosine,glucosylisomaltol,hydroxymethylfurfural,furfural,sugars,α-amylase,β-amylaseandcolourwereassessedduringtheproductionofwaterbiscuitsfromthreeeinkorn,threebreadandonedurumwheatflours.Heatdamageindices,colouranda_wdevelopmentduringbaking(from25to75minduration)ofwaterbiscuitsfromonebreadwheatwerealsostudied.Furosinewasmoreabundantindurum(86.0±6.29mg/100gprotein)andbreadwheat(42.5±6.93)thanineinkorn(15.7±3.92)waterbiscuits,whileGLIwasdetectedonlyindurum(10.0±2.02mg/kgDM)andbreadwheat(5.2±1.52)products;hydroxymethylfurfuralandfurfuralwerealwaysabsent.ThelimitedheatdamageofTriticummonococcumproductswasprobablyduetothemoderateβ-amylaseactivityofeinkorn,andhencetothelowmaltosecontentofitsmixes.Thecolourwascorrelatedtoheatdamage,aseinkornwaterbiscuitswerelighterthanthosefromotherwheats.

Teffisagluten-freecerealwithattractivenutritionalprofile.Thisresearchwasaimedtostudytheinfluenceofkilningontheenzymeactivitiesanddimethylsulphide(DMS)levelofDZ-Cr-387teffvarietyandsuggestakilningconditionthatyieldsteffmaltwithlowDMSwithnoorlittledamageonitsenzymeactivities.Themaltsweredriedusingisothermalconditionsat30,40,50,60and70°Cfor40hwithsamplingincertaintimeinterval.Tosetupkilningprogram,twotemperatureregimens18hat30°C + 1hat60°C + 3or5hat65°C(R1)and18hat30°C + 1hat60°C + 3or5hat80°C(R2)wereselected.Resultsfromisothermalkilningindicatedthatenzymeactivities,DMSandmoisturecontentswereaffected(P < 0.05)by=""time=""and=""temperature.=""the=""values=""of=""α-amylase,=""β-amylase,=""limit=""dextrinase=""activities=""and=""dms=""content=""while=""using=""the=""first=""regimen=""(r1)=""with=""3=""h=""curing=""at=""65°c=""were=""68=""u/g,=""440=""u/g,=""1,072=""u/kg=""and=""3.3=""mg/kg,=""respectively.=""whereas=""in=""the=""second=""regimen=""with=""3=""h=""curing=""at=""80°c,=""the=""values=""were=""42=""u/g,=""406=""u/g,=""736=""u/kg=""and=""2.15=""mg/kg,=""respectively.=""prolonged=""curing=""in=""both=""kilning=""regimens=""caused=""an=""adverse=""effect=""on=""the=""amylolytic=""enzyme=""activities.=""r1=""with=""shorter=""curing=""time=""is=""considered=""to=""be=""the=""best=""condition=""in=""preserving=""enzymes.=""the=""enzyme=""activities=""and=""dms=""level=""show=""that=""teff=""can=""be=""an=""alternative=""raw=""material=""for=""production=""of=""gluten-free=""malt.="">

Thedurationofpotatotuberdormancyhaseconomicimportanceforbothwarepotatoesandseedtubers.Theaimofthisstudywastoshedlightonthetimeatwhichtuberdormancyisinduced.Potatotuberswereselectedatdifferentstagesoftuberisation:initialswellingofthestolontipandearlystagesoftubergrowth(tuberdiameter3,7and14mm).Ateachstageoftuberisation,thediameterofthepithandthecortexwasmeasured,theactivityoftheenzymesbeta-amylase,glucose-6-phosphatedehydrogenaseandsuccinatedehydrogenasewasdetermined,andstarchandRNAlevelsrecorded.Itwasobservedthatduringtuberinitiationthepithandperimedullaryzoneshowedthegreatestincreaseinsize,whereasthecorticalparenchymaincreasedmainlywhenthetuberdiameterwas7-14mm.Moreover,duringstolonswellingandinitialtuberdevelopment(3mmdiameter)totalRNAaccumulationwasobserved.Starchaccumulationvariedwiththestagesofdevelopment.Glucose-6-phosphatedehydrogenaseandsuccinatedehydrogenaseexhibitedtheirhighestactivityduringstolonswellingwhereasbeta-amylaseactivitywashighestbothduringstolonswellingandatthe3mmdiameterstage.Fromthechangesintuberanatomy/morphologyandtheassaysofenzymeactivity,itisclearthatdormancyisnotinducedinallthetissuesofthetuberatthetimeoftuberinitiation,butisimposedontheindividualtissuesastheyareformed.Consequently,wemayreferto"tuberdormancy"onlywhenthelastbudhascompleteditsdifferentiation.

Maltingistargetedatgettingtheoptimumpointofenzymaticinductionwithoutlosingmuchenergyduringtheembryometabolismandgrowth.Successfulproductionofmaltincludesproductionofvarioushydrolyticenzymesandcontrolleddegradationofthegrainendospermstructure.AttentionisatthecentrestageofusingPearlmilletasasubstituteforbarley,wheatandsorghumduetothecostofimportationofbarleyandwheattotropicalcountries.ThisstudyseekstounderstandtheeffectofdifferentsteepingconditionswithrespecttovaryingpH,temperatureandtimeonkeyenzymesassociatedwithmaltingprocesses.Activitiesofα-amylase,β-amylase,β-glucanase,β-glucancontent,proteinprofilesweremonitoredwithrespecttothevaryingsteepingconditons.Therewasasteadyincrease(from0to96h)intheα-amylaseactivityat30°CunderallthepHstressconditionswiththeexceptionofacidicpHmaltedpearlmilletwheretheenzymeactivitydecreasedfrom191.04±1.5U/gto142.50±2.20U/gbetweenthe72ndand96thhour.Optimalactivity(248.04±0.20U/g)wasobservedat96hforalkalinepHsteepedpearlgrainsgerminatedat30°C.Howeveractivitydecreasesasgerminationdaysprolong.Optimalactivitywasrecordedatthe96thhourformaltedpearlmilletgrainssubjectedtoalkalinestress(2.73±0.20U/g)ascomparedwiththecontrol.β-glucanaseactivitiesofthemaltedpearlmilletgrainswerehighespeciallyunderthe30°Cheatstress.Peakactivitywasobservedatthe96thhourforthepearlmilletgrainssubjectedtoalkalinepHstress(892.34±0.20U/kg).β-glucancontentunderthealkalinepHstress,acidicpHstressandcontrolconditionsat30°Cwerewithinthesamerangeofapproximately4-8%w/wmaltflour.