衡水老白干酒发酵过程理化参数变化规律研究

The Change Rules of Physiochemical Parameters of the Fermented Grains of Hengshui Laobaigan during the Fermentation Process

研究了不同季节衡水老白干酒"三排净"工艺大茬酒醅理化参数在发酵过程中的变化规律,综合分析不同季节老白干酒的酒质差别。四季温度变化趋势基本相同,符合"前缓、中挺、后缓落"的规律,由高到低依次为夏>秋>春>冬,特别是酒醅上层温度差异更为明显。淀粉含量下降速率由高到低依次为冬>夏>春>秋,冬季淀粉含量下降速率明显高于其他三季。水分变化与乙醇变化规律一致。还原糖跟踪监测结果为秋>夏>春>冬,发酵中后期还原糖含量略有上升。酒醅酸度变化差异明显,发酵前期酸度上升缓慢,中后期春夏两季酸度上升迅速,秋季在最后5 d时酸度才急剧上升,冬季酸度一直未有明显上升,变化趋势与老白干"三排净"大茬乳酸乙酯变化规律一致。冬季乳酸、乙酸含量明显低于其他三季,整个发酵过程几乎没有明显上升的趋势,春、秋季乙酸在发酵过程中变化不大,而夏季乙酸含量在19 d时达到高峰后开始下降。实验证实,温度、淀粉、水分、还原糖、酸度、乳酸及乙酸等理化参数季节变化规律明显。

In this study, the change rules of physiochemical parameters of the fermented grains of Hengshui Laobaigan during the fermentation process in different seasons were investigated. Furthermore, the quality of liquor produced in different seasons was compared and analyzed. Specifically, temperature change trends were almost the same in four seasons （summer〉autumn〉spring〉winter, there was significant different in temperature of fermented grains in upper layer） in accord with the rule of ＂slow increase in prior period, stable in medium period, and slow decrease in late period＂. The decreasing rate of starch content ranked in decreasing sequence as winter〉summer〉spring〉autumn （the decreas- ing rate in winter was the highest among the four seasons）. The change rules of moisture content were the same as ethanol. The content of reducing sugar ranked in decreasing sequence in four seasons （autumn〉summer〉spring〉winter） and it slightly increased in late fermentation period. There was evident difference in the change of acidity of fermented grains, the change rules of which being the same as ethyl lactate （it increased slowly in prior fermentation period, it increased rapidly in late fermentation period in spring and in summer, however, it increased sharply in the final 5d in the fermentation in autumn, and it slightly increased in winter）. The content of lactic acid and acetic acid in winter was evidently lower than that in other three seasons, and there was no evident increase in the whole fermentation process, there was little change in acetic acid content in spring and in autumn, however, its content reached the peak at 19d after the fermentation and then dropped afterwards. This study proved that there was significant change rules in physiochemical parameters in different seasons.