Screening and application of Monascus in medium and high temperature Daqu

Abstract

Objective: The production process of esterified Monascus bran koji was optimized, and its effect on Luzhou-flavor liquor was explored. Methods: Five strains of Monascus were screened from Daqu, and the esterifying enzyme production ability of the strains was detected by the ester decomposition method. The strain with the most prominent enzyme production ability was selected to prepare Monascus bran koji. The koji-making process was optimized by single factor and orthogonal experiments and applied to liquor production. Results: Among the five strains, the J-3 strain had the strongest ability to produce esterification enzyme. Under the conditions of 50% moisture, 4% inoculation amount, pH 4.0 and 32 ℃ culture temperature, the esterification enzyme activity was as high as 77.78 mg/g bran koji. The bran koji was added to the fermented grains according to different inoculation amounts. Compared with the fermented grains without bran koji, when the inoculation amount of bran koji was 1%, the content of ethyl acetate in the fermented grains increased by 4.84 times, and the content of ethyl caproate increased by 3.55 times. When the inoculation amount was 1.5%, the content of ethyl butyrate increased by 4.72 times. The addition of esterified Monascus bran koji can improve the utilization rate of alcohol and starch, and significantly increase the total ester content in fermented grains. Conclusion: Adding Monascus bran koji to fermented grains according to the appropriate inoculation amount can improve the quality of Luzhou-flavor liquor.

Keywords

• monascus
• mouldy bran
• esterification force
• nongxiangxing baijiu