Optimization and application of Miqu prepared by Rhizopus oryzae from medium-high temperature Daqu

Abstract

Objective: A microbial enhancer with high-yield glucoamylase was developed from medium-high temperature Daqu and applied to the brewing of Daqu Baijiu for the yield increasing. Methods: Strains with high yield of glucoamylase was isolated from medium-high temperature Daqu and used to make Miqu. Miqu was employed as an enhanced starter in the brewing of Daqu Baijiu, and the yield of Baijiu were tested. Results: A strain M-1 with higher glucoamylase production was isolated and identified as Rhizopus oryzae. The results of the optimized conditions for Miqu making was as follows: bran and rice (2∶8), moisture content 45%, incubation time 72 h, drying temperature 40 ℃. Under the control of these conditions, the glucoamylase activity of Miqu is as high as 864.50 U/g. When appling the Miqu to the brewing of Daqu Baijiu, the results showed that when the addition amount of by, and the yield increased to 43.17% with the addition of 2% (weight of grain) M-1 Miqu. Conclusion: This study established a method for preparing Miqu from Rhizopus oryzae to improve the glucoamylase activity of medium-high temperature Daqu.

Keywords

• rhizopus oryzae
• daqu
• baijiu
• miqu
• glucoamylase activity