Study On Technology Of Composite Bacteria Fermented Wort

In order to promote the development and utilization of lactic acid bacteria and the development of cereals health drinks,in this paper Lactobacillus bulgaricus,Streptococcus thermophilus,Lactobacillus plantarum,Lactobacillus casei and Lactobacillus paracasei these five lactic acid bacteria were chose,activated by MRS medium and domestication cultivation with MRS and wort mixed media,making it suitable for the growth in wort.Drawing lactic acid bacteria’s growth and acid production curve in the wort medium and MRS medium.Comparing the situation of these five strains of lactic acid bacteria growth and acid production in MRS and wort,while evaluating the fermentation products in sensory.For mix fermentation wort,yeast was introduced on the basis of lactic acid bacteria fermentation and sensory evaluation was taken for the fermentation of wort product with different bacteria combinations,in order to pick a combination of two kinds of bacteria.To draw mix bacteria’s growth and acid production in wort in different conditions and to compare the situation of mixed fermentation in wort under different conditions,then taking the sensory evaluation of the fermentation production.Orthogonal experiment was designed on the basis of the conditions to further explore the combination conditions of lactic acid bacteria and yeast mixed fermented wort and drink test developed with sensory evaluation as an indicator of the beverage tasting,at the same time part physical and chemical indicators were detected.The results show that Lactobacillus bulgaricus, Streptococcus thermophilus,Lactobacillus plantarum, Lactobacillus casei, Lactobacillus paracasei these five domesticated species of lactic acid bacteria and their combinations adapt to the culture medium of wort,while the acid production of Lactobacillus bulgaricus combination of Streptococcus thermophilus in wort is best.Lactobacillus plantarum and Lactobacillus casei fermented wort in quality is poor.Mixed bacteria fermentation product’s quality is better than the single strain of bacteria’s.Depended on growth, acid production and sensory evaluation in the wort of five kinds of lactic acid bacteria alone or mixed with each other, lactobacillus bulgaricus and streptococcus thermophilus is relatively better combination.Through moderate yeast fermentation the jerky taste of original wort can be removed,while giving fermented products some broth flavor.Mixed lactic acid bacteria’s(Lactobacillus bulgaricus + Streptococcus thermophilus) growth and acid production is good on the adjusting medium which was moderately fermented by yeast. Mixed fermentation optimum conditions:the yeast’s inoculation is 4%(v / v) in 12 Bx wort and fermented 8h in 28 ℃,and then deal the fermentation broth with Pasteurization(using 64 ℃ water bath 30min) to inactivate yeast,using white sugar adjust sugar content to 12 Bx,then inoculate 2%(v / v) inoculum of combination of strain seed liquid of lactobacillus bulgaricus and streptococcus thermophilus(1: 1),fermented 12 h in 37 ℃.Mixed fermentation optimum conditions are not exactly the same with the conditions of bacteria’s growth and metabolism conditions and the condition should be adjusted according to different target.The fermented effect of yeast and lactic acid bacteria is relatively good in two-step method which can effectively achieve their performance maximization. During taking Two-step fermentation method, after yeast finished fermentation,whether inactivation has a very significant influence on the test results.This test confirmed that the development of two bacteria mixed fermented wort drinks have certain feasibility.