气相色谱-嗅闻-质谱联用仪(GC-O-MS)对黄酒麦曲中挥发性微量成分的研究

Analysis of Volatile Trace Compounds in Wheat Starter by GC-O-MS

麦曲是酿造黄酒重要的原料之一,对黄酒的风味起着重要的作用。通过固相微萃取结合气相色谱-闻香-质谱联用仪针对块曲、散生麦曲和爆麦曲进行定性分析,采用NIST质谱数据库和相对保留指数手段进行鉴定,发现麦曲中主要定性出50种化合物,包括酯类、醇类、醛类、烯类、酮类、烷烃类、苯环类和杂环类等,并能嗅闻出21种化合物。3种麦曲的香气存在着不同程度的差异,其中块曲和散生麦曲之间的差异较小,相对峰面积比例较高的物质主要包括醇类、烷烃类、杂环类和醛类;爆麦曲较其他2种麦曲的差异大,其主要物质为醇类、苯环类、醛类和杂环类。基于定性结果,针对麦曲中的19种化合物进行定量分析,采用固相微萃取结合气相色谱-质谱联用仪进行分析,发现自然接种的块曲中大多数酯类和醇类的风味含量最高;而经高温处理的爆麦曲中美拉德反应产物如2-甲基吡嗪、糠醛含量最高。以上说明不同种类的曲具有不同的特点,对于块曲,更有益于黄酒醇酯类风味的形成;而高温爆炒后的爆麦曲却有益于赋予黄酒特殊的风味。

Wheat starter is one of the most important raw materials for yellow rice wine production and it plays an important role in wine flavor. In this study, qualitative analysis of block starter, bulk wheat starter and stir-fried wheat starter were performed by GC-O-MS with NIST database and relative retention index for compounds identification. As a result, 50 kinds of compounds were idntified in wheat starter including esters, alcohols, aldehydes, alkenes, ketones, alkanes, benzodiazepines and heterocycles, and 21 kinds of compounds were smelt by olfactory receptor. There was some difference in volatile trace compounds among the three kinds of starter. Block starter and bulk wheat starter only had small difference and their main compounds included alcohols, alkanes, heterocycles and aldehydes. Stir-fried wheat starter had significant difference from other starter and its main compounds included alcohols, benzodiazepines, aldehydes and heterocycles. Based on the qualitative analysis results, 19 kinds of compounds were quantified by gas chromatograph-mass spectrometer with SPME, it was revealed that the content of ester compounds and alcohol compounds was the highest in naturally-inoculated block starter, the content of Maillard reaction products such as 2-methylpyrazine and furfural was the highest in stir-fried wheat starter. Generally, block starter produced more esters and alcohols in yellow rice wine, while stir-fried wheat starter produced more special volatile compounds in yellow rice wine.