Fermentation characteristics of Lactobacillus acetotolerans La50 from mash in Chi-flavor Baijiu production
Using Lactobacillus acetotolerans La50 isolated from mash in Chi-flavor Baijiu production as the research object,its growth characteristics,acid production capacity and tolerance were analyzed.It was applied to Chi-flavor Baijiu fermentation,and the fermentation characteristics were stud-ied.The results showed that L.acetotolerans La50 grew strongly,with a longer logarithmic phase(2-38 h),the optimal growth temperature was 37 ℃,and the optimal growth pH was 5.It could tolerate pH 3.0,7％NaCl,and 42 ℃ high temperature environment,which had a good environmental toler-ance.The total acid content was 18.49 g/L after fermentation at 37 ℃ for 72 h in modified MRS broth medium,which showed good acid-producing capacity.The lactic acid content in the fermentation broth was the highest[(19.14±0.36)g/L],followed by acetic acid[(4.08±0.24)g/L]and malic acid[(2.87±0.13)g/L],citric acid and succinic acid were not detected.The simulated brewing fermentation experiments showed that compared with the control group,the contents of total acid,total ester and lactic acid in the experimental group of simulated liquor samples were increased by 74.47％,189.19％and 179.23％,respectively.The total content of volatile flavor compounds increased,among them,the contents of esters and alcohols were increased by 311％and 13.94％,respectively,and the ethyl acetate content increased most significantly,which increased by 81.88％.In addition,hexyl acetate,diethyl octanoate,and acetic acid were detected only in the simulated fermented liquor samples of the experimental group.In conclusion,the strain had potential application value as a fermentation starter to enhance the flavor and taste of the Chi-flavor Baijiu.
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