发酵期间多粮浓香型白酒窖内黄水成分的变化趋势

通过定点连续提取窖内底层、中层、上层及窖边不同位置的黄水，对其常规指标及风味成分进行分析，通过研究黄水成分变化来反馈窖内发酵状态。结果表明，黄水中残余淀粉含量及残糖量随发酵时间延长而急降，20 d后趋于平缓；酒精度及酸度先升高后趋于平缓，发酵35～45 d时，酒精度及酸度最高，分别达6%vol～8%vol、4.8～5.6度，总体呈先产酒后生酸状态；黄水有机酸中乙酸含量最高，达2.0～2.8 g/L，丁酸、己酸、戊酸含量的变化趋势一致，且生成量与窖泥呈正相关，辛酸含量最低；黄水中乳酸乙酯、乙酸乙酯大量产生于主发酵期阶段，发酵10 d时，异丁醇与异戊醇均达最高，然后异戊醇缓慢下降而异丁醇相对恒定；无论含量高低，糠醛、乙醛、3-羟基-2-丁酮等均在第5～8天达到最高，随后急剧下降。

Change trend of Huangshui components in multiple-grains strong-flavor Baijiu fermentation pit during the fermentation period

The Huangshui (liquid residual of fermented grain) from the bottom layer, middle layer, upper layer and the side of the pit was continuously extracted at fixed points for routine index detection and flavor component analysis. The changes of components of Huangshui were studied to reveal the fermentation states in the pit. The results showed that the content of residual starch and residual sugar in the Huangshui decreased sharply with the extension of fermentation time, and then leveled off after 20 d. After 35-45 d of fermentation, Huangshui had the highest alcohol content and acidity, which were up to 6%vol-8%vol and 4.8-5.6, respectively, indicating that alcohol was firstly produced and then acid was produced. The content of acetic acid in organic acids was the highest, up to 2.0-2.8 g/L. The change of butyric acid, caproic acid and valeric acid content showed the same trend, the production was positively correlated with pit mud, and the content of caprylic acid was the lowest. The ethyl lactate and ethyl acetate in Huangshui were largely produced in the main fermentation stage. Isobutanol and isoamyl alcohol reached their peak values at 10 d of fermentation, and then isoamyl alcohol slowly decreased while isobutanol was relatively constant. Regardless of the content, furfural, acetaldehyde, 3-hydroxy-2-butylketone, etc. all peaked at 5-8 d and then decreased sharply.