西藏灵菇牛奶酒纯种复合发酵剂的研制

Study of the pure culture of Tibetan Mushroom starter

将从西藏灵菇中分离得到的乳酸菌L1、酵母菌Y1和工业菌种酵母菌Y2、乳酸菌Lb和St进行组合,采用L9(34)正交试验设计,确定出以上菌种发酵牛奶酒的最佳参数组合:酵母菌(Y1:Y2为1:1):乳酸菌(L1:Lb:St为1:1:1)为1:2,接种量为5%,发酵温度为37℃。通过对比试验,确定出各菌种的真空冷冻干燥较佳冻干保护剂配方,乳酸菌L1配方为10%脱脂乳、5%甘油、0.5%维生素C、1.5%明胶、10%蔗糖;酵母菌Y1和Y2配方为10%脱脂乳、5%甘油、1%L-半胱氨酸、10%蔗糖、10%麦芽糖。所得冻干菌种的发酵性能优良,能满足直投式纯种复合发酵剂的要求。

Strains isolated from native Tibetan Mushroom starter,lactobacteria L1 and yeast Y1,and industrialized strains,yeast Y2,lactobacteria Lb and St,were used to optimize the mixture of pure culture of Tibetan Mushroom starter.Orthogonal test design of L9（34） was used to arrange the tests.The optimal conditions for preparing the starter were obtained as yeast（Y1∶Y2=1∶1） to lactobacteria（L1∶Lb∶St=1∶1∶1） ratio of 1∶2,inoculation amount of 5%,fermentation at 37 ℃.Suitable protectants for freeze drying were obtained as a mixture of 10% skimmed milk,5% glycerol,0.5% Vc,1.5% gelatin for lactobacteria L1 and a mixture of 10% sucrose for L1;10% skimmed milk,5% glycerol,1% L-cysteine,10% sucrose,and 10% maltose for yeast strains of Y1 and Y2.The fermentation of freeze-dried bacteria obtained good performance,and was able to meet the requirements of ferment.