中高温大曲中红曲霉的筛选及应用

目的：优化酯化红曲霉麸曲的生产工艺，并探究酯化红曲霉麸曲对浓香型白酒的影响。方法：从大曲中筛选出5株红曲霉，采用酯分解法检测菌株产酯化酶能力，选择产酶能力最突出的菌株制备红曲霉麸曲。通过单因素及正交试验优化制曲工艺，并将其应用到白酒生产中。结果：5株菌株中产酯化酶能力最强的是J-3菌株，其在水分50%，菌株接种量4%，pH 4.0，培养温度32 ℃的条件下，可制得酯化酶活力高达77.78 mg/g的麸曲。将该麸曲按接种量不同添加到糟醅中发酵，较未添加麸曲的糟醅，在麸曲接种量为1%时，糟醅中乙酸乙酯含量提高了4.84倍，己酸乙酯含量提高了3.55倍。在接种量为1.5%时，丁酸乙酯含量提高了4.72倍。且添加酯化红曲霉麸曲能够提高酒精度与淀粉的利用率，显著提高糟醅中总酯含量。结论：将红曲霉麸曲按照适宜的接种量添加到糟醅中，能够提高浓香型白酒的质量。

Screening and application of Monascus in medium and high temperature Daqu

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.