五粮浓香型白酒发酵过程中黄水变化规律探究

Change Patterns of Huangshui in Wuliang Nongxiang Baijiu during the Fermentation Process

为探究五粮浓香型白酒发酵过程中黄水的理化指标及风味物质的变化规律,该研究通过对五粮浓香型白酒酒醅发酵过程中的黄水进行连续采样,检测黄水理化指标,结合顶空固相微萃取-气相色谱-质谱联用仪(HS-SPME-GC-MS)以及高效液相色谱(HPLC)分析黄水中的风味物质,比较不同天数的黄水理化指标和风味物质差异。结果表明,黄水pH值在整个发酵周期稳定在3.35~3.50;酸度在35 d达到最大值57.77 mmol/100 mL;淀粉和还原糖含量整体呈现下降趋势;酒精度在28 d达到最大值3.41%vol;固形物含量波动较大,与淀粉和还原糖含量变化存在一定关系;正交偏最小二乘法判别分析结果表明:不同发酵时期的黄水风味物质存在较大差异,变异权重参数值大于1的风味物质有11个,主要为酯类和酸类,其中乳酸乙酯及己酸乙酯大量产生于7~35 d,乙酸乙酯、丁酸乙酯在42~70 d大量积累。该研究获得了浓香型白酒发酵过程黄水物质变化规律,为后期选择黄水作为介质监控发酵过程提供了一定参考价值。

To explore the change patterns of the physical and chemical indicators as well as flavor substances of Huangshui during the fermentation process of Wuliang Nongxiang baijiu(NXB),Huangshui from the fermented grains of NXB was sampled continuously during the fermentation process to evaluate its physical and chemical properties.The flavor substances in Huangshui were analyzed by combining headspace solid-phase microextraction with gas chromatography-mass spectrometry(HS-SPME/GC-MS)and high-performance liquid chromatography(HPLC);thereafter,the physical and chemical indicators and flavor substances of Huangshui on different days were compared.The pH of Huangshui was stable at 3.35~3.50 throughout the fermentation period,and acidity peaked to reach 57.77 mmol/100 mL on the 35th day.The contents of starch and reducing sugars showed a decreasing trend,while alcohol content reaches a peak of 3.41%(volume)on the 28th day.The content of solids fluctuated greatly,which was related to changes in the contents of starch and reducing sugars.The results of orthogonal partial least squares discriminant analysis(OPLS-DA)showed large differences in flavor substances of Huangshui on different fermentation days,and the variable importance in projection(VIP)of 11 flavor substances,primarily esters and acids,exceeded 1.Ethyl lactate and ethyl hexanoate were produced in large quantities between the 7th and 35th days,whereas ethyl acetate and ethyl butyrate were accumulated in large quantities between the 42nd and 70th days.This study explored the change patterns of Huangshui during the fermentation process of NXB,which has a certain reference value for monitoring the NXB fermentation process with Huangshui as the medium.