Journal
INTERNATIONAL JOURNAL OF FOOD MICROBIOLOGY
Volume 250, Issue -, Pages 59-67Publisher
ELSEVIER
DOI: 10.1016/j.ijfoodmicro.2017.03.010
Keywords
Chinese liquor; Inoculation; Metabolic activity; Enzyme activity; Microbial community
Categories
Funding
- Priority Academic Program Development of Jiangsu Higher Education Institutions (111 Project) [111-2-06]
- National Key RD Program [2016YFD0400503]
Ask authors/readers for more resources
Chinese liquor is produced from spontaneous fermentation starter (Daqu) that provides the microbes, enzymes and flavors for liquor fermentation. To improve the flavor character of Daqu, we inoculated Bacillus licheniformis and studied the effect of this strain on the community structure and metabolic profile in Daqu fermentation. The microbial relative abundance changed after the inoculation, including the increase in Bacillus, Clavispora and Aspergillus, and the decrease in Pichia, Saccharomycopsis and some other genera. This variation was also confirmed by pure culture and coculture experiments. Seventy-three metabolites were identified during Daqu fermentation process. After inoculation, the average content of aromatic compounds were significantly enriched from 0.37 mg/kg to 0.90 mg/kg, and the average content of pyrazines significantly increased from 035 mg/kg to 5.71 mg/kg. The increase in pyrazines was positively associated with the metabolism of the inoculated Bacillus and the native genus Clavispora, because they produced much more pyrazines in their cocultures. Whereas the increase in aromatic compounds might be related to the change of in situ metabolic activity of several native genera, in particular, Aspergillus produced more aromatic compounds in cocultures with B. licheniformis. It indicated that the inoculation of B. licheniformis altered the flavor character of Daqu by both its own metabolic activity and the variation of in situ metabolic activity. Moreover, B. licheniformis inoculation influenced the enzyme activity of Daqu, including the significant increase in amylase activity (from 13 g starch/g/h to 1.7 g starch/g/h), and the significant decrease in glucoamylase activity (from 627.6 mg glucose/g/h to 445.6 mg glucose/g/h) and esterase activity (from 28.1 mg ethyl caproate/g/100 h to 17.2 mg ethyl caproate/g/100 h). These effects of inoculation were important factors for regulating the metabolism of microbial communities, hence for improving the flavor profile Daqu. (C) 2017 Elsevier B.V. All rights reserved.
Authors
I am an author on this paper
Click your name to claim this paper and add it to your profile.
Reviews
Recommended
No Data Available