泸型酒蒸馏前后酒醅中挥发性物质的差异性分析

Compositional discrepancy of volatile compounds in fermented grains and distilled grains of Luzhou-flavor liquor

利用顶空固相微萃取/气相色谱质谱联用技术(HS-SPME/GC-MS)检测了蒸馏前、后的泸型酒酒醅中挥发性化合物组成差异。结果表明,蒸馏前、后酒醅中各挥发性化合物种类相似,但相对含量差异明显。蒸馏后酒醅中醇类物质的相对含量比蒸馏前酒醅降低21.68%,而酸类、羰基类、酚类和酯类物质的相对含量分别提高了10.83%、6.68%、0.21%和4.08%。经过蒸馏后,大部分酯类化合物(除乙酸异戊酯、己酸丁酯、壬酸乙酯、乙酸苯乙酯)相对于内标的峰面积百分比均有不同程度的降低,说明这些酯类化合物有较高的蒸出效率,能够被大量蒸馏至基酒中。与此同时,一些酯类化合物在蒸馏过程中受热分解产生相应的酸类化合物,由于酸类物质沸点较高不易蒸出,大部分积累在蒸馏后酒醅中,参与下一轮发酵。

Composition of volatile compounds in fermented grains and distilled grains of Luzhou-flavor liquor were analyzed by headspace solid phase micro-extraction （HS-SPME） combined with gas chromatography mass spectrome- try （GC-MS）. The results showed that the compositions of volatile compounds in fermented grain and distilled grain were similar, while their relative contents were obviously different. After distillation, the relative content of alcohols in distilled grains reduced 21.68% compared with fermented grains, while the relative contents of acids, carbonyl compounds, phenolsand esters increased 10. 83% , 6.68% , 0.21% and 4.08% , respectively. The peak area percentages of most of esters （except isoamyl acetate, butyl hexanoate, ethyl nonanoate andphenethyl acetate） in distilled grains were less than those in fermented grains. This suggested that those esters were distilled to raw liquor more easily. At the same time, some acids were produced by the thermal decomposition of relevant esters. Because of the high boiling point, they were survived for the next round of fermentation.