Temperature is used for classifying Daqu as high temperature Daqu,medium temperature Daqu and low tem-perature Daqu,since it significantly affects the physical and chemical indexes and microbial community structure of Daqu.The effect of temperature varied in a small range during the manufacture of Daqu for Light-flavor baijiu brewing on its microbial and physicochemical properties is still unclear.In this study,the effect of microbial community structure and physicochemical properties of Hongxinqu by different peak-temperature were compared.The results showed that there was no significant difference in microbial alpha diversity between the two groups of Hongxinqu from different peak tem-perature.However,the microbial community structure at the genus level has changed significantly.In Hongxinqu samples from peak-temperature rised 5℃,Thermoascus increased from 64.7％to 78.4％,and Saccharomycopsis fibuligera de-creased from 33.3％to 15.2％,Eurotium and Rhizopus producing amylases were also significantly increased.Similarily,in Hongxinqu samples from peak-temperature rised 5 ℃,several bacteria genus significantly increased included Acetobacter,Weissella,and Staphylococcus,all of which were beneficial to the formation of Baijiu flavor,while Actinomycete Sac-charopolyspora which is little in general Daqu samples decreased from 26.7％to 8.8％.About of the physicochemical properties,when the peak-temperature increased by 5℃,the saccharification of Daqu decreased from 596.9 U to 516.1 U and the liquefaction decreased from 1.26 U to 1.05 U,but the decrease was not significant;The fermenting power and liquor-producing power have increased,with the fermenting power increasing from 0.74 U to 2.27 U and the liquor-pro-ducing power increasing from 7.1％vol to 8％vol.About of the physicochemical properties,the temperature increment of a small range did not significantly reduce the saccharification power and liquefaction power,while the fermenting power and liquor-producing power were increased.The overall results showed that increase of peak-temperature during Hongxin-qu making process according to the actual situation can effectively optimize the microbial community structure of Hongx-inqu and improve its comprehensive quality,which provided a theoretical basis for Hongxinqu production of high quality and highyield.
维普
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