酿酒酵母和异常毕赤酵母混菌发酵对白酒液态发酵效率和风味物质的影响

Effect of mixed culture of Saccharomyces cerevisiae and Pichia anomala on fermentation efficiency and flavor compounds in Chinese Liquor

摘要:

【目的】通过酿酒酵母(Saccharomyces cerevisiae)和异常毕赤酵母(Pichia anomala)在麸皮汁培养基中的混菌发酵, 以增加发酵液的风味酯含量并保证发酵效率。【方法】采用两种酵母混合接种、顺序接种混菌发酵方式, 以酵母单独接种发酵作对照, 测定酵母的发酵性能和发酵液中乙酸乙酯含量, 并对发酵结束时风味物质进行半定量; 利用无细胞系统, 分析两种酵母之间的相互作用。【结果】采用顺序接种混菌发酵方式, 避免S. cerevisiae对P. anomala的生长竞争性抑制, 使两种酵母均能获得较高的生物量; 发酵结束时, 乙醇浓度为20.17 g/L, 比酿酒酵母单菌种发酵时降低了9.14%; 但乙酸乙酯含量达到0.74 g/L, 比异常毕赤酵母单菌种发酵时提高了80%; 发酵液风味物质的测定结果表明, 酿酒酵母与异常毕赤酵母的混合发酵能够形成更多的酯类物质, 总酸和高级醇含量却相对较低, 有效改善了发酵液的风味特性; 在混菌发酵时, 碳源是影响酿酒酵母繁殖的重要因素, 但酵母的代谢物对异常毕赤酵母产生明显的抑制作用。【结论】混菌发酵, 为丰富发酵产物的风味复杂性和增强风格的独特性提供了一条有效的途径。

Abstract:

[Objective] To increase ester content and maintain fermentation performance, mixed fermentation of Saccharomyces cerevisiae and Pichia anomala in wheat bran liquid medium were used. [Methods] S. cerevisiae and P. anomala were inoculated using mixed or sequential modes. Fermentation efficiency and the content of ethyl acetate during fermentation process, and volatile compounds in ultimate fermentation liquid were detected with pure culture of yeast as controls. Interactions between yeasts were preliminarily studied through cell-free systems. [Results] Using sequential inoculation, growth of P. anomala wasn’t inhibited by S. cerevisiae and two species could reach high biomass. At the end of fermentation ethanol content was 20.17 g/L, which reduced 9.14% than pure culture of S. cerevisiae. But the concentration of ethyl acetate was 0.74 g/L, which increased 80% compared to P. anomala monoculture. The mixed fermentation of S. cerevisiae and P. anomala produced more esters, less alcohols and fatty, and improved flavor characteristics of fermentation liquid. Analysis of cell-free system showed that carbon source was an important factor to affect growth of S. cerevisiae and metabolites obviously inhibited propagation of P. anomala. [Conclusion] Mixed fermentations of S. cerevisiae and non-Saccharomyces provided a feasible way to improve flavor complexity and obtain speci?c characteristics of fermentation products.