Shelf stability of microbiology and physicochemical studies of zobo drink pasteurized and treated with preservative

Abstract

ABSTRACT Thecombinedeffectofpasteurization,improvedhygieneandvariedconcentrationsof sodium benzoateontheshelflifeandphysicochemicalpropertiesof‘Zobo’drinkwere evaluated.Freshlyprepared‘Zobo’drinksampleswereasepticallydispensedinto 100mLcapacityplasticbottlescontainingvariousconcentrationsofsodium benzoate (0.05%,0.25%,0.50%,0.75%and1.00%).Six‘Zobo’sampleswerepreparedfrom the calyxesofHibiscussabdariffausingmodifiedmethodthatcombinedtheuseofHACCP andHurdleTechnologyforpreservationandstoredontheshelfforeightweeks. AnalyseswerecarriedoutonaweeklybasiswithrespecttolossinvitaminCcontent, microbialqualityandphysicochemicalpropertiesofthebeverageforeightweeks. These parameterschanged significantly(p<0.05)with respectto the method of treatmentandstorageperiod.Pasteurizationat68oC for20minutessuccessfully eradicatedallcoliformsandpathogenicorganismsasnonewasisolatedfromthedrink throughout the eight weeks of shelf study. Lactobacillus fermentum and Saccharomycescerevisiaeisolatedfrom thecontrolsampleswereresponsibleforthe spoilageanddeteriorationofthebeverage.Althoughthefivedifferentconcentrationsofthepreservativeusedincombinationwithpasteurizationwereeffectiveinextendingthe shelflifeofthebeverage,sampleBz0.05%preservedbetterthanallotherswithout impartingnegativelyonthevitaminCcontentandotherphysicochemicalpropertiesof thedrink. Keywords:Zobodrink,SodiumBenzoate,Pasteurization,shelflif