多粮浓香型白酒糟醅中香气成分的空间分布规律

Spatial distribution of aroma compounds in fermented grains of multi-grains strong-aroma Baijiu

为了更清晰地认识多粮浓香型白酒酿造过程中糟醅对白酒香气的贡献度,利用顶空固相微萃取(headspace solid-phase microextraction,HS-SPME)偶联气质联用法(GC-MS)分析了糟醅香气成分的空间分布规律。结果表明,酯类和酸类是糟醅的主要香气成分,其含量的分布规律为下层>中层≥上层,同层糟醅距离窖壁越近含量越高且呈扩散递减趋势,窖边糟(0 cm)的酸类和酯类化合物含量最高分别为899.57和2792.91μg/g。醇类、芳香族、醛酮类成分的总含量并未呈现显著的空间异质性,部分物质如正己醇、正丁醇、正戊醇、邻甲酚、对甲酚、苯酚表现为下层>中层≥上层,同层糟醅中0 cm处含量最高。窖边糟醅中较高含量物质包括己酸、丁酸、己酸乙酯、丁酸乙酯、己酸己酯和己酸丁酯等。该研究对全面认识糟醅在酿酒中的作用具有一定的借鉴意义。

To better understand the aroma contribution of fermented grains in Baijiu fermentation,spatial variation of aroma compounds in strong-aroma Baijiu fermented grains were investigated by the headspace solid-phase microextraction coupled with gas-chromatography mass spectrometry.The results showed that acids and esters were the main compounds in fermented grains with the spatial distribution of bottom layer>middle layer≥upper layer.It was found that higher concentration of these two compounds was detected in fermented grains closer to the cellar wall,and the concentrations of acids and esters decreased from 0 cm to 100 cm position.The highest concentration of acids and esters(899.57μg/g and 2792.91μg/g)were found in fermented grains at 0 cm position.Although no obvious trend of spatial distribution was detected in alcohols,aromatics,aldehydes and ketones,compounds including 1-hexanol,1-butanol,1-pentanol,p-cresol,o-cresol and phenol presented a concentration trend of bottom layer>middle layer≥upper layer and showed the highest levels in 0 cm fermented grains within the same layer.The volatile compounds having high concentrations in fermented grains at 0 cm position included hexanoic acid,butanoic acid,ethyl caproate,ethyl butyrate,hexyl hexanoate and butyl hexanoate.The results illustrated the spatial distribution of aroma compounds in fermented grains and provided reference for an overall understanding the contribution of fermented grains for multi-grains strong-aroma Baijiu fermentation.