Analysis On High-temperature Daqu And Functional Bran Koji Of Baiyunbian Liquor

In this study,we selected Baiyunbian high-temperature Daqu as the research object,the change rule of microbial quantity,dominanted bacterias and physicochemical property in the storage process were analysed.Different storage time of high temperature daqu were simulated fermentation in laboratory and discussed its influence on liquor flavor,aimed at providing certain theoretical basis for Daqu production,storage,using and shortening storage time.The result showed that,yeasts were not detected from Daqu,bacterias were in the majority,mold below four months storage could be checked out.With the storage period increased from 0 months to four months,the number of bacteria and mold did not decrease but increse at first,the number of bacteria and mold reached the highest at four-mounth and when it was over four-mouth,they bagan to fall.Ten strians of bacteria isolated from Daqu were identified by 16 S rDNA identification as seven species,including Bacillus licheniformis,Bacillus sp.,Bacillus cereus,Bacillus subtilis,Bacillus tequilensis,Bacillu amyloliquefaciens,Bacillus methylotrophicus.With the storage period increased from 0 mouth to six months,Bacteria species gradually reached the highest as five at four-mouth,then over four-mouth it gradually fall to one.B.methylotrophicus existed in each of the storage period of daqu and was absolutely the dominated strain.With the storage period increased from 0 mouth to six months,the The moisture of Daqu did not change much;the fermenting power of Daqu rised slowly on the whole;Saccharifying power of Daqu reached the highest at four-month then decreased,while the number of mold had the same change rule,which showed that the strength of the saccharifying power was directly related to mold number.Laboratory simulation fermentation test of different storage time of Daqu showed that four-month Daqu had obvious advantage in ethanol fementation and ester fementation than other Daqu,while saccharifying power and fermenting power of four-month Daqu was the strongest.Comprehensive comparison,four-month Daqu was best for liquor production.In this study,eight strains of yeast of different species isolated from fermentated grain were compared to gain several strains which had good tolerance,strong ethanol-producing and low propyl alcohol-producing.Selectd those yeast as yeast bran koji,adding those yeast bran koji to the process to research its influence on liquor flavor after solid-state fermentation conditions were optimized.Compared seven strains yeast isolated from fementationed grain,it showed that Pic3,Isc5,Sac5,Scc7 could grow at 42℃,broomcorn saccharified fermentation test showed that Scc7 had obvious advantage in ethanol fementation and produced least normal propyl alcohol than other six yeast.Comparing to the standard strain 1056,Scc7 had stronger ethanol resistance ability.And in the broomcorn saccharified medium fermentation test,its yield of alcohol increased by 8.7%,ethyl acetate increased by 22.2% and normal propyl reduced by 9.9%.Selected Scc7 as the functional bran koji,its optimal fermentation conditions were moisture content of 55%,temperature of 30 ℃ for 30 h.Mixing Scc7 with 1-month daqu for simulation test for 15 d,comparing by only adding 1-month daqu,its yield of alcohol increased by 62.8% and normal propyl reduced by 46.2%.Mixing Scc7 with 1-month daqu for simulation test for 30 d,comparing by only adding 1-month daqu,its yield of alcohol increased by 55.5% and propyl alcohol reduced by 48.49%;Comparing by only adding 4-month daqu alcohol content increased by 20.8% and propyl alcohol content reduced by 57.78%.The experimental results show that the Scc7 had a good application in liquor-making.