不同氮源组成麦汁对酿酒酵母发酵性能的影响

Effect of worts with different nitrogen compositions on fermentation performance of brewer's yeast

研究了酿酒酵母Saccharomyces pastorianus(FBY0095)在六种不同氮源组成麦汁(20°P)中生物量、表观发酵度、乙醇浓度以及游离氨基氮(FAN)消耗量等指标的差异。结果表明,在20°P超高浓麦汁发酵中,麦汁氮源含量和组成对酵母发酵性能具有显著影响。随着麦汁中可同化氮量的提高,加速了酵母对糖的吸收利用,提高了酵母稳定期生物量和乙醇产量,发酵时间缩短了20%。当氮源匮乏(约为FAN=124.59 mg/L)时,补充适量大豆分离蛋白水解物(SPIH)于超高浓麦汁中,增加了麦汁氮源的多样性,使菌体增长量提高8.3%,乙醇产量提高4.43%,是酵母生长的有效氮源。

Six kinds of very high gravity worts（20 °P）with different nitrogen compositions were used to examine their effects on the biomass accumulation,degree of fermentation, ethanol yield and FAN consumption of brewer＇s yeast （FBY0095）in this study.Results showed that fermentation performance of yeast was strongly affected by both of the level and the composition of nitrogen during very high gravity fermentation（20 °P）.With the increases of sugars consumption rates, biomass, ethanol yield and the decrease of fermentation time by 20% were observed with the increase of the amounts of nitrogenous compounds in wort. When the nitrogen source was insufficient（ about FAN = 124.59 mg/L）, wort supplemented with appropriate soy protein isolate hydrolysates（SPIH）induced the increases of biomass and ethanol yield by 5.03% and 4.43%, respectively, and the diversity of nitrogen sourch was increased which indicated that SPIH was an effective nitrogen source for yeast growth with a more complex nitrogen composition.