Study On Main Microflora Of Daqu Of Special Flavor Type

Daqu, as saccharifying agent and fermentive agent in the production of Daqu liquor, contains multiple microbes and various enzymes. Daqu microbes species and quantities are quite different in different liquor production enterprises. Daqu microbes come from raw materials, air, venue, coverage of the straw and so on. In Daqu liquor production process they gradually formed the microflora which was naturally given, exceptionally complex and compatible with the environmental. Therefore, through the research of Daqu and environment microbes quantity and species change rule, can improve the Daqu quality and also has an important significance in researching the influence of microflora on liquor style. Through analysis of Daqu and environment microflora, the main results are as follows:(1)In special flavor types of Daqu making stage, there were most bacteria, followed by mold, yeasts at least. Bacteria quantity continuously increased in the beginning of making stage,16th days reached highest peak, then began to decline. And the proportion of bacillus from 21% to 46%, and the species of bacillus gradually increased. Yeast quantity gradually reduced in making stage, but 10th days to 16th days increased. And the proportion of ascosporogenous yeast from 26% to 33%. Mold quantity increased in the beginning of making stage,16th days reached highest peak, then began to decline. Mucor and Rhizopus were dominant mold in making stage, the proportion more than 90%.(2)In special flavor types of Daqu storage stage, the number of microbes reduced rapidly in previous two months and then smoothly. Bacteria quantity from 3.28 X 108/g to 2.38 X 106/g in storage stage, bacillus was dominant bacteria in storage stage, the proportion from 46% to 93%. Yeast quantity 1.36 X 106/g in the beginning of storage stage, and then reduced continuously, there was no yeast in Daqu that was stored more than three months. The proportion of ascosporogenous yeast in previous two months of storage stage was increasing. Mold quantity from 2.76 X 107/g to 5.24 X 106/g, Mucor and Rhizopus were still dominant mold.(3)Compared quantities and species of microbes in the different quality Daqu, it is found that mainly bacteria in quality Daqu are bacteria and mold, bacillus is dominant bacteria, Mucor and Rhizopus are dominant mold. The number of microbes in poor quality Daqu more than high quality Daqu, and the species of microbes are quite different in different quality Daqu.(4)Study on main microflora of Daqu-room environment and Daqu materials, it is found that there is no yeast in wall dust, Acetobacter and Acidomonas are the dominant bacteria, Aspergillus and Penicillium are the dominant mold; there is no mold in vinasse, Acetobacter is the dominant bacteria, Candida^ Torulopsis and Saccharomyces are the dominant yeast.