CURDLAN-可得然胶、凝胶多糖、热凝胶.pdf

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1、CURDLANPreparedatthe57thJECFA(2001)andpublishedinFNP52Add9(2001),supersedingspecificationspreparedatthe53rdJECFA(1999)andpublishedinFNP52Add7(1999).AnADI“notspecified”wasestablishedatthe57thJECFA(2001).SYNONYMSBeta-1,3-glucan;INSNo.424DEFINITIONCurdlanisahighmolecularweightpol

2、ysaccharideconsistingofβ-1,3-linkedglucoseunits,producedbypure-culturefermentationfromanon-pathogenicandnon-toxicogenicstrainofAgrobacteriumbiovar1(identifiedasAlcaligenesfaecalisvar.myxogenesatthetimeofdiscovery)orAgrobacteriumradiobacter.Curdlanconsistsofβ-(1,3)-linkedglucos

3、eresiduesandhastheunusualpropertyofforminganelasticgeluponheatingitsaqueoussuspension.C.A.S.number54724-00-4Chemicalformula(C6H10O5)nStructuralformulaAssayNotlessthan80%(calculatedasanhydrousglucose)DESCRIPTIONOdourlessoralmostodourless,whitetonearlywhitepowder.FUNCTIONALUSESF

4、irmingagent,gellingagent,stabilizer,thickener.CHARACTERISTICSIDENTIFICATIONSolubility(Vol.4)Insolubleinwaterandethanol.SolubilityinalkaliPassestestSuspend0.2gofthesamplein5mlofwater,add1mlof3Nsodiumhydroxide,andshake.Thesampledissolves.GelformationHeata2%aqueoussuspensionofthe

5、sampleinaboilingwaterbathfor10minandcool.Afirmgelforms.PrecipitateformationwithPassestestcuprictartrateSeedescriptionunderTESTSPURITYGelstrengthNotlessthan600g/cm²(2%aqueoussuspension)SeedescriptionunderTESTSpH(Vol.4)6.0-7.5(1%aqueoussuspension)Lossondrying(Vol.4)Notmorethan10

6、%(60ºfor5h,invacuum)Sulfatedash(Vol.4)Notmorethan6%Test1gofthesample(MethodI)Nitrogen(Vol.4)Notmorethan0.3%Test1gofthesample(MethodII)Lead(Vol.4)Notmorethan0.5mg/kgDetermineusinganatomicabsorptiontechniqueappropriatetothespecifiedlevel.Theselectionofsamplesizeandmethodofsample

7、preparationmaybebasedontheprinciplesofthemethoddescribedinVolume4,“InstrumentalMethods.”MicrobiologicalcriteriaTotalplatecount:Notmorethan1,000cfu/g(Vol.4)E.coli:Negativein1gTESTSIDENTIFICATIONTESTSPrecipitateformationAdd5mlofsulfuricacidTSto10mlofa2%aqueoussuspensionofthewith

8、cuprictartratesample,heatinaboilingwaterbathfor30minandcool.N