基于黄水线上下层酒醅及基酒的风味特征分析

Analysis of flavor characteristics of fermented grains above and below the Huangshui line

为探究浓香型白酒黄水线上下层的出窖酒醅及其基酒风味物质的差异,以典型窖池的黄水线以上酒醅(上层)和黄水层酒醅(下层)为研究对象,采用顶空固相微萃取-气相质谱联用法对上下层糟醅以及出窖糟醅蒸馏酒中的挥发性风味物质进行分析,同时对两层酒醅中主要的差异性物质在发酵过程含量变化规律进行分析。结果表明,糟醅中检出136种风味物质,基酒中检出152种风味物质,上下层糟醅风味物质总量和基酒风味物质总量存在显著差异性(P<0.05);以出窖酒醅及其基酒挥发性风味物质建立了不同层次的糟醅以及基酒的正交偏最小二乘判别分析,根据模型的变量权重系数(variable importance in projection,VIP)与相对百分含量大于1%筛选出18种主要差异化合物;酒醅与原酒中共有差异性风味物质正丙醇、正丁醇、正己醇、己酸乙酯、乳酸乙酯、己酸含量差异性显著(P<0.05),分析差异性风味物质发酵过程中的变化规律发现其在发酵后期含量变化较大。该研究解析了浓香型白酒黄水上下层酒醅的风味差异,结果可为浓香型白酒风味物质形成机制以及调控发酵模式提供数据支撑。

In order to investigate the differences of the flavor compounds of the two layers of fermented grains in Nongxiangxing Baijiu(NJ)above(FG-A)and below(FG-B)the Huangshui line.Thus,in a typical distillery plant,characterization of volatile compounds of FG-A and FG-B was evaluated.The flavor compounds in fermented grains were detected via head space solid-phase micro-extraction combined with gas chromatography of mass spectrometry,and the content variation of the main different flavor compounds in the two layers fermented grains was analyzed during the fermentation process.The results showed that 136 flavor compounds and 152 flavor compounds were detected in fermented grains and base wine,respectively.Significant differences were observed in quantity and content of flavor compounds between FG-A and FG-B during NJ fermentation process(P<0.05),and quantity and content of flavor compounds of base wine was significantly different in FG-A and FG-B(P<0.01).The orthogonal partial least squares-discrimination analysis was borrowed for finding different flavor compounds of fermented grains and base wines in FG-A and FG-B,and 18 discriminant markers of volatile compounds were found by the weight coefficient of variables(VIP>1)and relative percentage content above 1%.The n-propyl alcohol,Butanol,Hexanol,ethyl caproate,ethyl lactate,caproic acid,were discriminant markers of volatile compounds in fermented grains and raw wine,have significantly different(P<0.01),and found varied greatly the content of these discriminant markers in the late stages of fermentation.Thus,the present study highlighted differences of volatile compounds in the two layers of fermented grains in NJ fermentation,and provided data support for the formation mechanism of flavor substances and the regulation of fermentation mode of NJ.