Development Of New Compound Vegetable Starter And Quality Analysis Of Fermented Products

Two lactic acid bacteria strains L1 and L5 were optically separated from Chinese pickled cabbages.According to physiological and biochemical methods and 16S rDNA sequences analysis,results indicated that L1 was Lactobacillus paracasei(GenBank accession NO.:HQ615722)and L5 was Lactobacillus buchneri(GenBank accession NO.:HQ615721).Then Bacillus coagulans(B.c)was mixed with L1 and L5 together,based on the the results of fermentation experiments,the best proportion of L1,L5 and B.c is confirmed at 1:2:2?1:2:3,as confirmed by high L-lactic acid output and best fermenting results.The compound lactic acid bacteria powder was prepared by freeze-drying method.And the sensory quality of pickled cabbage can be improved after 1.Og/L CaCl2 and 20mg/L natamycin added.CaCl2 and natamycin can be mixed in the vegetable starter as an additional agent.Therefore,the new compound vegetable starter prepared by 1g compound lactic acid bacteria power(Cell content of ?1 ×1010cfu/g),200mg natamycin,and 10g CaCl2,which can ferment about 10kg Chinese cabbage.The optimal mixed culture condition is as follows:In pH6 MRS medium,the inoculums proportion of L1,L5 and B.c was set at 1:3:5.B.c was firstly inoculated in the medium,and cultured at 43 ? for 12h,then L1 and L5 were inoculated and mixedly cultured for another 12h.The total biomass was 1.7 × 109cfu/mL,with L1,L5 and B.c strain proportion at 1:1.97:2.84,which met the approximal ratio of new compound vegetable starter.The mixed culture method does not change the growth trendancy and consumption curves of both carbon and nitrogen sources,indicating that no significant interactions among the three strains under the mixed culture system.The cabbage fermented using new compound vegetable starter excelled in sensory,nutritional quality and safety than those fermented by natural fermentation.The development of the new compound vegetable starter improves quality and safety of tradition fermentation food by modern biotechnology,and it also fills the balnk of the vegetable starter market in our country.