异味是姜味白酒香气恶化的最常见和最严重的原因之一。然而,导致异味的关键化合物及其形成机制尚不清楚。这项研究从1种正常和5种类型的异味发酵谷物中鉴定出271种挥发性化合物(腐烂,酸败,泥浆,发霉,并燃烧)通过顶空固相微萃取结合气相色谱-质谱法。使用VIP和OAV分析,47种关键风味化合物,包括吲哚,苯酚,异戊醇,二乙酰,乙酸,异丁酸,发现异戊酸可以区分正常和异味的发酵谷物。此外,40个微生物属(主要是红曲霉,肠球菌,Dyadobacter,奥托维亚,假黄单胞菌,窄食单胞菌,假单胞菌,和黄单胞菌)与这47个化合物显着相关(p<0.05,Pearson相关)。最后,构建了异味化合物形成的代谢途径。本研究为姜味白酒发酵过程中的异味成分及其潜在形成机理提供了全面的信息。
Off-flavor is one of the most frequent and serious causes for the aroma deterioration in Jiang-flavor Baijiu. However, the key compounds and their formation mechanism responsible for off-flavor are still unclear. This study identified 271 volatile compounds from 1 normal and 5 types of off-flavor fermented grains (putrid, rancidity, mud, musty, and burnt) by headspace solid-phase microextraction combined with gas chromatography-mass spectrometry. Using VIP and OAV analysis, 47 key flavor compounds including indole, phenol, isoamyl alcohol, diacetyl, acetic acid, isobutyric acid, and isovaleric acid were found to distinguish normal and off-flavor fermented grains. Furthermore, 40 microbial genera (mainly Monascus, Enterococcus, Dyadobacter, Ottowia, Pseudoxanthomonas, Stenotrophomonas, Pseudomonas, and Xanthomonas) were significantly (p < 0.05, Pearson correlation) related to these 47 compounds. Finally, metabolic pathways for off-flavor compounds formation were constructed. This study provides comprehensive information on the off-flavor compounds and their potential formation mechanism during Jiang-flavor Baijiu fermentation.