啤酒酵母乙醛代谢关键酶相关性研究

Correlation of key enzymes of acetaldehyde metabolism in beer yeast

乙醛是啤酒中的主要风味物质,其代谢主要来自酵母细胞。酵母中乙醇脱氢酶及乙醛脱氢酶是乙醛代谢的关键酶,对乙醛变化起着重要作用。跟踪啤酒酵母发酵过程中相对酶活力及乙醛变化,发现两种乙醇脱氢酶和乙醛脱氢酶的相对酶活力与发酵过程乙醛含量变化具有一定相关性。同时对低产乙醛啤酒酿酒酵母kb2-4与出发菌株啤酒酵母kb进行发酵试验,跟踪检测相对酶活力及乙醛含量,其乙醇脱氢酶Ⅰ和乙醇脱氢酶Ⅱ及乙醛脱氢酶相对酶活力均高于出发菌株,平均增幅分别为15.5%,11.6%和5%。3种酶活性的变化协同作用可以使乙醛含量降幅最大为33.8%。

Acetaldehyde is the main flavor substance in beer, and its metabolism mainly occurs in yeast cells. Alcohol dehydrogenase （ADH） and alde- hyde dehydrogenase （ALDH） in yeast are the key enzymes in the acetaldehyde metabolism, which plays an important role in the changes of acetaldehyde. By tracking the relative enzyme activity and acetaldehyde changes during beer yeast fermentation process, the results showed the relative enzyme activity of two kinds of ADH and ALDH had certain relevance with the changes of acetaldehyde content during fermentation process. At the same time, in the fermentation test of low yield acetaldehyde beer brewing yeast kb2-4 and original strain beer brewing yeast kb, the relative enzyme activity and the acetaldehyde content were determined. The relative enzyme activity of ADH I, ADH II and ALDH were higher than that of the original strain, and the average growth rates were 5%, 11.6% and 15.5%, respectively. The synergistic effect of the three kinds of enzyme activity changes could make the acetaldehyde content decreasing amplitude to the maximum of 33.8%.