Megazyme/Galactomannan Assay Kit/K-GALM/100 Assays per kit

Anenzymictechniquehasbeendevelopedfortherapidandaccuratequantitationofthegalactomannancontentofguarseedsandmillingfractions.Thetechniqueinvolvesthemeasurementofthegalactosecomponentofgalactomannansusinggalactosedehydrogenase.Thegalactomannansareconvertedtogalactoseandmanno-oligosaccharidesusingpartiallypurifiedenzymesfromacommercialpreparationandfromgerminatedguarseeds.Simpleprocedureshavebeendevisedforthepreparationoftheseenzymes.Applicationofthetechniquetoanumberofguarvarietiesgavevaluesforthegalactomannancontentrangingfrom22.7to30.8%ofseedweight.

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%.

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

Galactomannangumsarewidelyusedinthefoodandoilindustries,andthereisconsiderableinterestinapplyingbiotechnologicalapproachestoimprovetheirphysicalproperties.Amannansynthasefromguar(Cyamopsistetragonoloba)wasexpressedunderthecontrolofabeanβ-phaseolinpromoterintransgenicMedicagotruncatula.AlthoughtheexpressionofexogenousmannansynthasecausedaslightdecreaseingalactomannanlevelsinMedicago,themolecularweightandviscosityofthepolymerweresignificantlyincreased,althoughthemannosetogalactoseratioanddegreeofpolydispersityremainedunchanged.Atthesametime,expressionofabout2.8%ofthegeneswasalteredsignificantlyintheseedsoftransgenicMedicagolinesanalysedbyAffymetrixgenomechip,withaparticularlystrikinginductionofputativetrehalosephosphatesynthasegenes.Mannansynthaseexpressionalsocausedlargealterationsinthelevelsofanumberofsugarsandsugaralcohols,suggestingthatover-expressionofaprocessiveglycosyltransferaseperturbsthemechanismsofsugarsensingand/orhomeostasis,possIBLyinvolvingsignallingviatrehalose-6-phosphate.

Guargalactomannan(referredtoasguargum)isaversatilepolysaccharide,obtainedfromtheseedsoftheshrubCyamopsistetragonolobus,whichfindsseveralapplicationsineitheritsnativeorchemicallymodifiedform.Fortextileprinting,guargumcanalsobepartiallydepolymerisedinordertopromotedyepenetration,improveswellinginwaterandachievethedesiredrheologicalproperties.Guargumisobtainedfromguarseedsbyathermo-mechanicalprocessthatleavesca.3%oflargelyinsolubleproteinsinthegum,originatingfromtheendospermsaleuronelayer.Whenprintingsilkfabricswithacidorpremetalliseddyes,guarendogenousinsolubleproteinsbindtightlytoanionicdyes,causingdepositionofcolouredaggregatesonthefabric.Thiscausesimperfectionsontheprintedfabricintheformoftiny,butvisible,‘dots’,whichlowersthequalityofthefinalarticles.Inordertoeliminate‘dotting’,anovelprintingthickenercomposedofdepolymerisedguargummixedwithabioengineeredsubtilisinproteasehasbeendeveloped.Uponsolubilisationofthegum,andduringpreparationoftheprintingpastemixture,theproteasehydrolysesguarguminsolubleproteins,generatingsolublepeptidesthatarewashedoffbythepost-printingtreatmentsofthefabric.Thisenzymaticapplicationprevents‘dotting’andsignificantlyimprovesthequalityofthesilkprint,withoutanymeasurabletensilestrengthlossofthefabric.

Thisstudyexaminedtheinfluenceofdifferentresistantstarch(RS)varietiesandconventionalfibresontheefficiencyofnutrientutilisationandintestinalfermentationinpigs.Thirty-sixpigs(30kg)werefedpoultrymeal-baseddietssupplementedwith10%granularresistantcornstarch(GCS),granularresistantpotatostarch(GPS),retrogradedresistantcornstarch(RCS),guargum(GG)orcellulosefor36daccordingtoacompletelyrandomisedblockdesign.Distalilealandtotaltractrecoveriesweresimilar(P>0•05)amongtheRSvarieties.Distalilealstarchrecoverywashigher(P<0•05)=""in=""pigs=""consuming=""the=""rs=""diets=""(27–42=""%)=""as=""compared=""with=""the=""control=""group=""(0•64=""%).=""consumption=""of=""gcs=""reduced="">P<0•05)=""apparent=""total=""tract=""digestibility=""and=""whole-body=""retention=""of=""crude=""protein=""in=""comparison=""with=""the=""control=""group.=""consumption=""of=""gps=""reduced="">P<0•05)=""total=""tract=""ca=""digestibility=""and=""whole-body=""retention=""of=""ca=""and=""p=""compared=""with=""the=""control=""group.=""however,=""consumption=""of=""rcs=""increased="">P<0•05)=""total=""tract=""ca=""digestibility=""compared=""with=""the=""control=""group.=""caecal=""butyrate=""concentration=""was=""increased="">P<0•05)=""following=""consumption=""of=""rcs=""and=""gg=""in=""comparison=""with=""the=""control=""group.=""consumption=""of=""all=""the=""rs=""varieties=""reduced="">P<0•05)=""caecal=""indole=""concentrations=""compared=""with=""the=""control.=""caecal=""butyrate=""concentrations=""were=""positively=""correlated="">P<0•05;="">r0•63–0•83)withthermalpropertiesamongtheRSvarieties.WeconcludethatnutrientutilisationandintestinalfermentationaredifferentiallyaffectedbytheconsumptionofdifferentRSvarietiesandtypesoffibres.ThermalpropertiesassociatedwithdifferentRSvarietiesmaybeusefulMarkersfordevelopingRSvarietieswithspecificfunctionality.

TheaimofthisstudywastoassesstheproductiveandqualitativetraitsofseedsofsixguargenotypescomingfromIndia,SouthAfricaandtheUSA,growninaMediterraneanenvironment,bothforindustrialuse(galactomannans)andasanimalfeed(guarmeal).Yieldofthesixvarietiesrangedfrom1.49tha^-1to2.05tha^-1.Galactomannancontentreachedvaluesfrom28.6g/100gto34.6g/100gwiththehighestsignificativevalueexhibitedbyIndiangenotype,LewisandSouthAfricangenotype.Galactomannanyieldresulted0.55tha^-1,onaverage,withsmalldifferencesamonggenotypes.Themeanvaluesofproteincontentoftheguarseedsshowedanaveragevalueofallthegenotypesof283g/kgonaDMbasisof896g/kgwiththesignificantlyhighestvaluesinIndianandSouthAfricangenotypes.Lipids(onaDMbasis)wasof28.3g/kgDMonaverage,withthesignificantlyhighestvalueinSouthAfricanandIndiangenotypes.CrudeFibre,rangedfrom107to122g/kg.Thefibrousfractionswereonaverage496g/kgDM,133g/kgDMand5.08g/kgDMforNDF,ADFandADL,respectively.Polyphenolsrangedfrom3.61mggallicacid/gofMatadorto6.63mggallicacid/gofKinmanandtanninsfrom2.01mg/gofcatechinequivalentsofKinmanto4.05mg/gofcatechinequivalentsofSouthAfricangenotype.Monumentshowedthehighestcontentofn6-PUFA,whereas,thehighestcontentofn3-PUFAwasobservedinIndiangenotype.Theration3/n6PUFA,theAtherogenicandThrombogenicindicesunderlinethehighqualityofguaroilforhumanandanimalnutrition.Thisstudyunderlinesthedoubleaptitudeofguarseedofgumextractionandtheby-product,assessing,respectively,itsproductivetraitsforindustrialuseandnutritionaltraitsforincreasingitsuseinfeedstuffintheMediterraneancrop-livestocksystem.Thisdoubleuserepresentsanimportantaddedvaluetopromotethewidespreadcultivationofthecrop.