复合霉菌产酯化酶工艺优化及强化发酵白酒挥发性代谢物差异研究

Optimization of esterifying enzyme production by compound mould and difference of volatile metabolites in intensified fermentation of Baijiu

中文关键词:  响应面  混合培养  酯化酶  代谢物

英文关键词:response surface  mixed culture  esterification enzyme  intensified fermentation  volatile metabolites

中文摘要:

      目的 研究霉菌混合培养条件对产酯化酶的影响, 比对强化发酵后白酒挥发性代谢物差异。方法 在前期单因素实验的基础上, 通过响应面法确定霉菌混合培养最佳工艺, 并以混合霉菌强化发酵白酒, 结合主成分分析分析传统发酵与强化发酵白酒挥发性代谢物之间的差异。结果 使用响应面法确定培养时间4 d, 培养温度32℃, 接种量3%, 接种比例红曲霉:米曲霉:根霉质量比为2:2:1条件下混合霉菌产酶能力得到显著提升, 酶活为263.17 U/g, 相比提高了104.6 U/g; 混合霉菌强化发酵的白酒, 在酒精度与挥发性物质方面均优于自然发酵白酒, 且以15%替代大曲强化发酵白酒效果最佳。强化发酵后, 异戊醇、苯乙醇、乙酸乙酯、己酸乙酯、正己酸、棕榈酸乙酯含量均高于自然发酵白酒, 风味物质含量提升, 对白酒的品质提升可能具有直接影响。结论 通过响应面法得到了产酶最优条件, 进而实现混合霉菌强化大曲, 为后期深入研究通过改良大曲对白酒质量控制研究提供参考。

英文摘要:

      Objective To study the effects of mixed culture conditions of mold on esterifying enzyme production, and compare the differences of volatile metabolites in Baijiu after intensified fermentation. Methods On the basis of the previous single factor experiment, the optimum process of mixed culture of molds was determined by response surface method, and the mixed molds were used to strengthen the fermentation of Baijiu. The difference of volatile metabolites between traditional fermentation and enhanced fermentation Baijiu was analyzed by principal component analysis. Results The response surface method was used to determine the culture time of 4 days, the culture temperature of 32℃, the inoculation amount of 3%, and the inoculation ratio of Monascus:Aspergillus oryzae:Rhizopus mass ratio of 2:2:1. The enzyme production capacity of the mixed mold was significantly improved, and the enzyme activity was 263.17 U/g, which was 104.6 U/g higher than that of the control group. Mixed mold enhanced fermentation Baijiu was superior to natural fermentation Baijiu in terms of alcohol content and volatile substances, and 15% replacement of Daqu enhanced fermentation Baijiu had the best effect. After intensive fermentation, the content of isoamyl alcohol, phenylethyl alcohol, ethyl acetate, ethyl caproate, hexanoic acid and ethyl palmitate were higher than those of naturally fermented Baijiu, and the content of flavor substances increased, which may have a direct impact on the quality improvement of Baijiu. Conclusion The optimal conditions for enzyme production are obtained by response surface method, and then the mixed mold enhanced Daqu is realized, which provide a reference for further research on the quality control of Baijiu by improving Daqu.