Study On The Dynamic Changes Of Microbial Flora And Analysis About Major Flavor Components During The Process Of Ditty Liquor's Mechanical Brewing

New mechanized brewing technology,overthrows the traditional production of Xiaoqu liquor.Therefore,microbial species,the growth and decline law and produced major flavor will change,In order to explore the Xiaoqu liquor mechanized brewing mechanism,improve the yield and quality of liquor,therefore study on the saccharification,fermentation process of dynamic changes of all kinds of microorganisms and flavor of the product is imperative.The fermented grains in the process of mechanical brewing has been studied in this thesis,tracking the saccharification and fermentation process,being analyzed by traditional separation and culture method and 16S rDNA,ITS rDNA analysis tools,isolating and identifying bacteria,yeast and fungi species.On this basis,the plate colony counting is used to study the growth and decline law of bacterial,fungal,tracing and analyzing the dynamic change of the fermented grains in temperature,water content,total acid,pH,reducing sugar,starch and ethanol content during the brewing process,as well as adopting HPLC and headspace gas chromatography to test the change of fermented grains'main flavor liquor,and then relating these change to every physicochemical index,to explore the generating law of the main flavor liquor in the process of mechanical brewing.The main results are as follows:?1?Isolated from 41 strains of microbes in fermented grains,17 strains of bacteria,17 strains of yeast and 9 strains of fungi were separated successfully,17 strains of bacteria were identified in 8 genus,17 strains of yeasts were identified from 5 genera,9 strains of fungi were identified from 4 genera,they are initially distinguish between beneficial bacteria and harmful bacteria,and analyze their biological safety.?2?The number of bacteria in the saccharification period has been declining,during fermentation increased initially and then decrease and increase then decrease,reached a maximum value of 1.48×10¹³/g fermented grains at 11 d.The number of yeast was increased after the first downward trend in the saccharification period,during fermentation was increase firstly and then decrease and then increase and then decrease trend.Fungal counts were increased and then declined in saccharification and fermentation process.?3?During the saccharification,temperature,reducing sugar,water content,total acid,and ethanol content increased,pH and starch content decreased.The early stage of the fermentation,temperature,pH,water content,total acid,reducing sugar,starch and ethanol content change is bigger,the late fermentation to stabilize.?4?Testing the flavor substances in the four major categories:alcohols:isobutanol,n-butanol,iso-amyl alcohol and fusel oil;aldehydes:isobutyraldehyde,isovaleraldehyde isovaleraldehyde,aldehyde and acetal;acids:acetic acid and lactic acid;ester:content variation in the brewing process of ethyl acetate,ethyl butyrate,ethyl lactate,etc.Physicochemical index and flavor substance content dynamics,the growth and decline law of microorganisms in fermented grains were carried out based on the analysis of correlation,initially revealed the causes of the unique flavor of wine:brewing temperature"first high to low";sugar consumption of"fast slow";flora growth"first fungi post bacteria";metabolites of alcohol before incense".