低氮对酿酒酵母发酵过程中酯类物质合成的影响

采用顶空固相微萃取-气相色谱-质谱法（HS-SPME-GC-MS）测定了不同程度低氮胁迫下的模拟葡萄汁酒精发酵过程中酯类物质的含量。结果表明，低氮并没有改变各种酯类物质的生成规律，但影响了其发酵结束时酯类物质的含量。在发酵过程中，乙酸乙酯、己酸乙酯、辛酸乙酯和癸酸乙酯的含量逐渐增加；丁酸乙酯的含量在发酵第8天达到最大值后逐渐降低；乙酸异戊酯的含量先增加后在发酵第12天时达到最低值后又迅速增加；乙酸苯乙酯的含量在发酵前期（发酵4～6 d）迅速达到一个峰值，随后其含量缓慢降低；低氮胁迫下酯类物质的总量降低，其中乙酸苯乙酯和癸酸乙酯的含量增加，乙酸乙酯、乙酸异戊酯、丁酸乙酯和己酸乙酯的含量降低。因此，在葡萄酒的生产过程中可适当提高氮源浓度来提高酯类物质含量。

Effect of low nitrogen stress on esters formation during fermentation by Saccharomyces cerevisiae

The effects of different nitrogen concentrations on esters contents during alcoholic fermentation of synthetic must were determined by HS-SPME-GC-MS. The results showed that the formation rules of various esters were not changed under low nitrogen stress, but it affected the content of esters at the end of fermentation. During fermentation, the contents of ethyl acetate, ethyl caproate, octanoic acid and ethyl acetate gradually increased, and the content of ethyl butyrate in the fermentation reached the maximum at 8 d, then gradually decreased. The content of isoamyl acetate in fermentation increased firstly and then decreased, it reached the lowest value at 12 d and then increased rapidly. The content of phenethyl acetate rapidly reached a peak at the early stage of fermentation (4-6 d), and then decreased slowly. The total amount of the esters, the yield of phenethyl acetate and ethyl caprate increased, the contents of ethyl acetate, isoamyl acetate, ethyl butyrate and ethyl caproate decreased under low nitrogen stress. Therefore, the contents of esters could be improved in the wine production by appropriately increasing nitrogen content.