Research On The Application Of Functional Microorganisms In The Production Of Maotai-flavor Liquo

The study and application of functional brewing microorganism is helpful to analyze the characteristics and formation mechanism of liquor flavor substances in solid fermentation.This topic is to study the functional microorganism of Maotai-flavor liquor.The high-temperature resistant alcohol-producing saccharomyces cerevisiae and enzymic bacillus were screened from fermented soy sauce and high-temperature Daqu.One strain of high-temperature alcohol-producing saccharomyces cerevisiae and one strain of enzymic bacillus subtilis were obtained through tolerance test,growth characteristics study and molecular biology identification.The interaction between saccharomyces cerevisiae and Bacillus subtilis was studied.In order to improve the mixed fermentation ratio of saccharomyces cerevisiae and Bacillus subtilis,and applied in the production of Maotai-flavor liquor,in order to understand the interaction of functional microorganisms in the process of Maotai-flavor liquor brewing,and the impact on production and brewing,to enhance the stability and efficient production of liquor to provide favorable theoretical guidance.（1）Screening and identification of target strains.Thirty-seven strains of yeast were isolated from samples of fermented soy sauce.Four strains（Y18,J14,J18 and Y14）were found to be heat-resistant and capable of producing alcohol after being screened by lethal temperature test,TTC chromogenic test and fermentation test.According to morphological and 26Sr RNA identification,all the four strains were saccharomyces cerevisiae.After the tolerance study,the J18 saccharomyces cerevisiae strain with ethanol tolerance concentration of 18%vol,strong fermentation ability,maximum fermentation temperature of 44℃and heavy fermentation flavor was obtained.Forty strains were isolated and screened from high-temperature Daqu powder and fermented grains.The XB-3 strains with relatively high activity of amylase and protease were screened by using the preliminary screening of enzyme producing transparent circle and the re-screening of enzyme producing liquid.The activity of amylase and protease were 3.96 U/m L and 50.31 U/m L,respectively.According to the morphological and16Sr RNA identification,the XB-3 strain was Bacillus subtilis.（2）Mixed liquid fermentation of the target strain.When the mixed fermentation ratio of saccharomyces cerevisiae and Bacillus subtilis was 1:10,the growth trend of mixed fermentation was similar to that of pure culture.Because saccharomyces cerevisiae will produce acid substances during the growth process under mixed fermentation conditions,the p H of fermentation environment drops to about 5.0,resulting in slightly acidic fermentation environment,which inhibits the growth of Bacillus subtilis,so that the growth trend under mixed fermentation conditions decreases in the late fermentation period.Reducing sugar consumption was the fastest,the reducing sugar concentration was less than 1.0 g/L on the 5th day,and the reducing sugar content was almost 0 on the 6th day.Ethanol yield was the highest,reaching 14.9g/L.The highest CO₂ weight loss was 10.05 g.（3）Application of functional strains in Maotai-flavored liquor.The practical application of the strains is mainly carried out by simulated fermentation in laboratory and practical application in winery.In laboratory simulation fermentation,the alcohol content of mixed fermentation was 39%vol,which was higher than that of fermented grains.The analysis of physical and chemical properties showed that the water content of mixed fermentation increased slightly,the acidity of mixed fermentation was moderate,and the consumption of starch and reducing sugar was high.The sensory evaluation of fermented grains showed that the fermented grains had a heavy flavor of sauce and wine.By analyzing the volatile components of the wine samples,it was found that there were more kinds of compounds in mixed fermentation,and the contents of alcohol compounds and ester compounds were higher than other components.In the actual use of the distillery,the three rounds of production of the distillery were tested.According to the analysis of the data of each link,the mixed fermentation alcohol accuracy increased by 4～5%vol,the increment of wine production increased by12～15kg,and the wine yield increased by 3～4%.By comparing the volatile substances in the experimental group of the three rounds with the corresponding control group,it was found that the contents of alcohols and esters in each round experimental group increased significantly,and the contents of acids and aldehydes also increased slightly,among which the aldehydes in the second round had a small reduction,mainly the reduction of acetaldehyde content.But too much acetaldehyde can make a wine taste rough and spicy,so less acetaldehyde is good for the body.