发酵工艺参数对嫩啤酒抗氧化力的影响

为提高啤酒的抗氧化力及改善其风味稳定性,系统研究了麦汁发酵过程中抗氧化力的变化及发酵工艺参数包括麦汁浓度、酵母接种量、酵母代数与发酵温度对嫩啤酒抗氧化力的影响。结果表明:麦汁发酵过程中DPPH自由基清除活性、氧自由基吸收能力和还原力分别提高了6.27%、3.46%和31.38%。麦汁浓度从6°P增加到12°P,嫩啤酒的DPPH自由基清除活性、氧自由基吸收能力与还原力升高显著,浓度超过12°P后,抗氧化指标增速减缓或略有下降。酵母接种量在800～3200万个/mL之间的嫩啤酒抗氧化力随酵母接种量的增加而升高。1、2、4和5代酵母发酵嫩啤酒的抗氧化力随酵母代数的增加呈降低趋势。9、12和15℃发酵嫩啤酒的抗氧化力随发酵温度的升高而降低。因此,优化发酵工艺参数是提高啤酒抗氧化力的有效措施。 

Effects of fermentation process parameters on the antioxidant activity of green beer

The evolution of antioxidant activity during wort fermentation and the effects of fermentation process parameters including the wort gravity, yeast inoculation amount, yeast generation and fermentation temperature on the antioxidant activity of green beer were studied systemically in order to improve the antioxidant activity and flavor stability of beer. Results showed that wort fermentation resulted in significant increases of 6. 27%, 3. 46% and 31. 38% in DPPH radical scavenging activity, oxygen radical absorbance capacity and reducing power for green beer, respectively. The increase of wort gravity (from 6 to 12°P) led to significant increases in DPPH radical scavenging activity, oxygen radical absorbance capacity and reducing power of green beer, whereas slow growth or slight decrease in antioxidant indices was detected when the wort gravity exceeded 12°P. In the range of 8 to 32 million/mL, the higher yeast inoculation amount resulted in the higher antioxidant activity of green beer. From 1 up to 5 generation, the antioxidant activity of green beer declined as the yeast generation increased. Furthermore, the antioxidant activity of three green beers (fermented at 9, 12 and 15℃, respectively) decreased with the rise of fermentation temperature. Thus, it might be one of effective measures to improve antioxidant activity of beer by optimizing the fermentation process parameters.