Study On The Brewing And Physicochemical Properties Of Liquid Fermentation Liquor By Daqu And Bran Koji

As China's national liquor,liquor has a long history and is deeply loved by people.The traditional brewing method of Chinese liquor is a very complex naturalfermentation process,which uses microbial growth and metabolism to saccharify starch in grain into fermentable sugar,and then uses yeast to convert sugar into alcohol,and then distills liquor.Microorganisms play an important role in this process.Daquplays the role of saccharifying agent and aroma producing agent in the process of liquormaking.The saccharifying power of Bran Koji is better than Daqu,and the liquor yield is higher.However,there is a lack of flavor substances in liquor produced by Bran Koji,which leads to poor liquor quality.In this paper,the liquid fermentation methodwas used.Daqu and Bran Koji were combined.Rice bran was the main raw material.Wheat and malt were added as raw materials for liquor making.Liquor was brewed by high temperature accumulation and liquid fermentation.The main results are as follows:1.Wheat Bran Koji was prepared by pure culture technology.The effects of culture time and water content on glucoamylase activity of bran koji were determined.It is obtained that the glucoamylase ability of the Bran Koji is better when the moisture content of the bran is55%for 72 hours.2.For the research of the liquid fermentation process,set up a single factor experiment to explore the influence of the ratio of raw materials,the ratio of Daqu to Bran Koji,the amount of koji added,the ratio of material to water and the fermentation time on the alcohol content,total acid and total ester,and then select the raw materials The ratio,the ratio of Daqu to bran koji,the amount of koji added,and the ratio of material to water are used as optimization factors for the orthogonal experiment.Through the analysis of the results of the orthogonal experiment,the four best combinations are:A₂B₁C₁D₁,A₂B₃C₂D₂,A₂B₃C₂D₃,A₂B₁C₂D₂.A verification test was conducted on the best combination,and the combination A₂B₁C₂D₂was obtained as the best fermentation conditions for liquid fermentation in this experiment.The conditions were that the ratio of raw materials was 55%:19%:26%,Daqu:Bran Koji was 2:1,and the amount of rice added Liquor brewed with a ratio of 25%and a ratio of material to water of 1:3 is better.3.The physical and chemical properties of the base wine brewed with the best fermentation conditions obtained through the above experiments were tested,and the alcohol content was 35.8%vol,the total acid content was 1.215g/L,and the total ester content was1.523g/L.The methanol content is 0.014g/L,the solid content is 0.203g/L,according to the detection of GC-MS method,the relative percentage of furfural is 0.090%.4.A total of 30 substances were detected in the detection of flavor substances in laboratory-made liquid fermentation base wines using GC-MS detection technology.Among them,ester substances are the most kind,including 16 kinds,and also contain a small amount of acids,aldehydes,and alcohols.There are 5 kinds and 2 kinds of alkane and other substances.A total of 20 substances were detected in the laboratory solid-state fermentation base wine.The ester substance contains up to 12 kinds.There are also a small amount of aldehydes,phenols,alkanes and other substances.Acids and alcohols are not detected.The presence.It can be concluded that the process of liquid fermentation of Daqu and Branqu Liquor is feasible,and the method of using rice bran as the raw material for brewing can be realized,hereby making it possible to reduce the consumption of my country's main grains.