Novelsubstratesfortheautomatedandmanualassayofendo-1,4-β-xylanase.
Mangan,D.,Cornaggia,C.,Liadova,A.,McCormack,N.,Ivory,R.,McKie,V.A.,Ormerod,A.&McCleary,D.V.(2017).CarbohydrateResearch,445,14-22.
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endo-1,4-β-Xylanase(EC3.2.1.8)isemployedacrossabroadrangeofindustriesincludinganimalfeed,brewing,baking,biofuels,detergentsandpulp(paper).Despiteitsimportance,arapid,reliable,reproduc
IBLe,automatableassayforthisenzymethatisbasedontheuseofachemicallydefinedsubstratehasnotbeendescribedtodate.Reportedhereinisanewenzymecoupledassayprocedure,termedtheXylX6assay,thatemploysanovelsubstrate,namely4,6-
O-(3-ketobutylidene)-4-nitrophenyl-β-4
5-
O-glucosyl-xylopentaoside.ThedevelopmentofthesubstrateandassociatedassayisdiscussedhereandtherelationshipbetweentheactivityvaluesobtainedwiththeXylX6assayversustr
ADItionalreducingsugarassaysanditsspecificityandreproducibilitywerethoroughlyinvestigated.
Comparisonofendolytichydrolasesthatdepolymerize1,4-β-D-mannan,1,5-α-L-arabinanand1,4-β-D-galactan.
McCleary,B.V.(1991).“EnzymesinBiomassConversion”,(M.E.HimmelandG.F.Leatham,Eds.),ACSSymposiumSeries460,Chapter34,pp.437-449.AmericanChemicalSociety,Washington.
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Hydrolysisofmannan-typepolysaccharidesbyβ-mannanaseisdependentonsubstitutiononandwithinthemain-chainaswellasthesourceoftheβ-mannanaseemployed.Characterisationofreactionproductscanbeusedtodefinethesub-sitebindingrequirementsoftheenzymesaswellasthefine-structuresofthepolysaccharides.Actionofendo-arabinanaseandendo-galactanaseonarabinansandarabinogalactansisdescribed.Specificassaysforendo-arabinanaseandarabinan(infruit-juiceconcentrates)arereported.
Measurementofendo-1,4-β-D-xylanase.
McCleary,B.V.(1992).“XylansandXylanases”,(J.Visser,G.Beldman,M.A.Kusters-vanSomeronandA.G.J.Voragen,Eds.),ProgressinBiotechnology,Vol.7,Elsevier,SciencePublishersB.V.,pp.161-169.
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Variousproceduresforthemeasurementofxylanaseinfermentationbroths,commercialenzymemixtures,breadimprovermixturesandfeedsamplesaredescribed.Problemsassociatedwiththeroutineuseofreducing-sugarbasedmethodsaxehighlightedandtheadvantagesandlimitationsofviscometricanddye-labelledsubstrateproceduresformeasurementoftracelevelsofactivityinfeedsamplesarediscussed.
Newdevelopmentsinthemeasurementofα-amylase,endo-protease,β-glucanaseandβ-xylanase.
McCleary,B.V.&Monaghan,D.(2000).“ProceedingsoftheSecondEuropeanSymposiumonEnzymesinGrainProcessing”,(M.Tenkanen,Ed.),VTTInformationService,pp.31-38.
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Overthepast8years,wehavebeenactivelyinvolvedinthedevelopmentofsimpleandreliableassayprocedures,forthemeasurementofenzymesofinteresttothecerealsandrelatedindustries.Insomeinstances,differentprocedureshavebeendevelopedforthemeasurementofthesameenzymeactivity(e.g.α-amylase)inarangeofdifferentmaterials(e.g.malt,cerealgrainsandfungalpreparations).Thereasonsfordifferentproceduresmaydependonseveralfactors,suchastheneedforsensitivity,easeofuse,robustnessofthesubstratemixture,orthepossibilityforautomation.Inthispresentation,wewillpresentinformationonourmostup-to-dateproceduresforthemeasurementofα-amylase,endo-protease,β-glucanaseandβ-xylanase,withspecialreferencetotheuseofparticularassayformatsinparticularapplications.
Analysisoffeedenzymes.
McCleary,B.V.(2001).“EnzymesinFarmAnimalNutrition”,(M.BedfordandG.Partridge,Eds.),CABInternational,pp.85-107.
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Enzymesareaddedtoanimalfeedtoincreaseitsdigestibility,toremoveanti-nutritionalfactors,toimprovetheavailabilityofcomponents,andforenvironmentreasons(CampbellandBedford,1992;Walshetal.,1993).Awide-varietyofcarbohydrase,protease,phytaseandlipaseenzymesfinduseinanimalfeeds.Inmonogastricdiets,enzymeactivitymustbesufficientlyhightoallowfortherelativelyshorttransittime.Also,theenzymeemployedmustbeabletoresistunfavourableconditionsthatmaybeexperiencedinfeedpreparation(e.g.extrusionandpelleting)andthatexistinthegastrointestinaltract.Measurementoftracelevelsofenzymesinanimalfeedmixturesisdifficult.Independentoftheenzymestudied,manyoftheproblemsexperiencedaresimilar;namely,lowlevelsofactivity,extractionproblemsinactivationduringfeedpreparation,non-specificbindingtootherfeedcomponentsandinhibitionbyspecificfeed-derivedinhibitors,e.g.specificxylanaseinhibitorsinwheatflour(Debyseretal.,1999).
Measurementofpolysaccharidedegradingenzymesusingchromogenicandcolorimetricsubstrates.
McCleary,B.V.(1991).ChemistryinAustralia,September,398-401.
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Enzymicdegradationofcarbohydratesisofmajorsignificanceintheindustrialprocessingofcerealsandfruits.Intheproductionofbeer,barleyisgerminatedunderwelldefinedconditions(malting)toinducemaximumenzymesynthesiswithminimumrespirationofreservecarbohydrates.Thegrainsaredriedandthenextractedwithwaterundercontrolledconditions.Theamylolyticenzymessynthesizedduringmalting,aswellasthosepresentintheoriginalbarley,convertthestarchreservestofermentablesugars.Otherenzymesactonthecellwallpolysaccharides,mixed-linkageβ-glucanandarabinoxylan,reducingtheviscosityandthusaidingfiltration,andreducingthepossibilityofsubsequentprecipitationofpolymericmaterial.Inbaking,β-amylaseandα-amylasegivecontrolleddegradationofstarchtofermentablesugarssoastosustainyeastgrowthandgasproduction.Excessquantitiesofα-amylaseintheflourresultinexcessivedegradationofstarchduringbakingwhichinturngivesastickycrumbtextureandsubsequentproblemswithbreadslicing.Juiceyieldfromfruitpulpissignificantlyimprovedifcell-walldegradingenzymesareusedtodestroythethree-dimensionalstructureandwaterbindingcapacityofthepecticpolysaccharidecomponentsofthecellwalls.Problemsofroutineandreliableassayofcarbohydratedegradingenzymesinthepresenceofhighlevelsofsugarcompoundsareexperiencedwithsuchindustrialprocess.
Optimisingtheresponse.
Acamovic,T.&McCleary,B.V.(1996).FeedMix,4,14-19.
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Afinebalanceexistsbetweenenzymeactivityandtheadverseeffectsassociatedwithfeedprocessing.Accurateestimationofenzymeactivityinthefeedisapre-requisitetooptimisingtheresponse.
XylanaseBfromthehyperThermophileThermotogamaritimaasanindicatorfortemperaturegradientsinhighpressurehightemperatureprocessing.
Vervoort,L.,VanderPlancken,I.,Grauwet,T.,Verjans,P.,Courtin,C.M.,Hendrickx,M.E.&VanLoey,A.(2011).InnovativeFoodScience&EmergingTechnologies,12(2),187-196.
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Withinthescopeofhighpressurefoodsterilization,animportantissuethatshouldbetakenintoaccountinrefiningprocessandequipmentdesignisthetime-andposition-dependenttemperaturegradientthatexiststhroughoutthepressurevesselandtheproductload.Sinceenzymesfromthermophilicmicroorganismsshowgood
Prospectsforthedevelopmentofindicatorstomapoutthetemperaturenon-uniformityinhighpressurehightemperature(HPHT)processing,inthiswork,thepotentialofxylanaseBfrom
Thermotogamaritima(XTMB)wasinvestigated.Itsinactivationatisothermal–isobaricconditionswasbestdescribedbyafirst-ordermodel.Thepressuredependenceofthe
DvalueswasnegligibleatHPHT,thetemperaturedependencehoweverwassubstantial.TheThermalDeathTime(TDT)model,anditscorrespondingparameters,describingthislargetemperaturedependenceweresuccessfullyvalidatedunderdynamicprocessingconditions,relevantforindustrialHPHTapplications.IndustrialrelevanceDespiteextensiveresearchprogressonhighpressurehightemperature(HPHT)processingasanewfoodsterilizationtechnique,foodindustryshouldbeawareofapossiblenon-uniformtemperaturedistribution,occurringinthepressurevesselanditsconsequenceforthequalityandsafetyoftreatedproducts.Sincedirectmeasurementofthetemperaturedistributionisnotfeasiblewiththemeasuringdevicescurrentlyavailableandconstructivecomputationofthetemperatureprofilebynumericalsimulationisinadequate,thedevelopmentofspecifictemperature-sensitivewirelesssensors,orpressure–temperature–timeindicators(pTTIs)canbeputforward.Inthiswork,xylanaseBfrom
Thermotogamaritima(XTMB)wasevaluatedasapotentialenzymaticindicatorformappingthetemperaturenon-uniformityinHPHTprocessing.
IdentificationofmultiplehighlysimilarXIP-typexylanaseinhibitorgenesinhexaploidwheat.
Takahashi-Ando,N.,Inaba,M.,Ohsato,S.,Igawa,T.,Usami,R.&Kimura,M.(2007).BiochemicalandBiophysicalResearchCommunications,360(4),880-884.
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Inhexaploidwheat,
Xip-IistheonlyXIP-typexylanaseinhibitorgenewhoseexpressionandfunctionhavebeencharacterizedindetail.HerewedemonstratetheexistenceofnewXIP-typegeneswiththeidentificationof
Xip-R1and
Xip-R2intheroot
CDNAs.Southernblotanalysiswiththe
Xip-R1proberevealedthatXIP-typegenescomprisedasignificantlygreatergenefamilythanpreviouslyspeculatedoninstudieswiththe
Xip-Iprobe.Thetranscriptlevelof
Xip-Rgeneswasincreaseduponaninoculationwith
Erysiphegraminisintheleaves,butnotwith
Fusariumgraminearuminthespikelets.RT-PCRwiththeRNAsamplesfollowedbyextensivesequencingoftheclonedamplifiedproductsrevealedthepresenceof12highlysimilar
Xip-Rgenes.Amongthesegenes,
Xip-R1wastheonlypredominant
Xip-Rfamilymemberinducedtoexpressinresponseto
E.graminis.
XIP-R1waslocatedintheapoplasticspaceandinhibitedfamily11xylanases,buttheproteindidnotshowchitinolyticactivity.TheseresultssuggestthathexaploidwheathasalargefamilyofXIPsinitsgenome,butthatonlysomeofthemareexpressedforplantdefenseinlimitedtissues.
Sproutedwheatasanalternativetoconventionalflourimproversinbread-making.
Marti,A.,Cardone,G.,Nicolodi,A.,Quaglia,L.&Pagani,M.A.(2017).LWT-FoodScienceandTechnology,80,230-236.
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Sproutingisanaturalprocessthatenhancesthenutritionalandsensoryprofileofcereal-basedfoods.Thepresentworkaddressedthepossibilityofusingrefinedflourfromsproutedwheat(SWF)toimprovethebread-makingperformanceofsomefloursinplaceofconventionalimprovers-i.e.enzymaticimprover(EI)andmalt(M).Either0.5%EIorMwasaddedtothecontrolflour(CTRL),asconventionallyusedinbakeries,whereasSWFwasusedupto2%.UnlikelyEIandM,1.5%SWFshowedaglutenaggregationstrengthsimilartothatoftheCTRL,suggestingnoworseningoftheproteinnetworkcharacteristics.Asfortheleaveningproperties,doughdevelopmentincreased,thankstotheenrichmentwith1.5%SWF.Inaddition,presenceofSWFimprovedtheamountofgasproductionduringleavening-resultinginbreadwithhighspecificvolume-andthecrumbsoftnessduringstorage.AdditionofSWFmayrepresentavalidalternativetoenzymaticimproversormaltforimprovingthetechnologicalperformanceofwheatflours.