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投稿时间：2020-11-04
投稿时间：2020-11-04
中文摘要: 糙米酒是我国的一种特色发酵酒，其独特风味不仅来自原料，更与其酿造微生物有关，而微生物的低温后发酵作用对产品最终品质具有决定影响。该文主要采用高通量测序技术和气质联用技术分析糙米酒后发酵期的菌种和风味物质变化，以期确定糙米酒后发酵期的优势菌和主要风味物质以及最佳后发酵期。结果表明，对于真菌，整个后发酵期中酿酒酵母菌为绝对优势菌种，平均丰度为93.90%。其它两种真菌即未分类毕赤氏酵母属菌种、卷枝毛霉的最高相对丰度分别为11.47%和8.32%。对于细菌，整个后发酵期中干酪乳杆菌和短乳杆菌为优势菌种，其丰度分别为85.72%和10.68%，后发酵第7天发现了污染的杂菌弯曲假单胞菌和铜绿假单胞菌，这两种污染菌在随后的后发酵期内又显著降低。对于挥发性风味物质，主要包括11种酯、3种醇、2种酮及1种酚。其中，相对含量最高、种类最多的化合物为酯类，达60%～80%，代表物质有棕榈酸乙酯、亚油酸乙酯、油酸乙酯，其次是相对含量为15%～30%的醇类，代表物质为β-苯乙醇、正癸醇、2-甲基-1-丁醇。含量最高的棕榈酸乙酯在后发酵阶段的相对含量先降后升，0～14 d由33.06%降至26.90%，14 d～28 d增加至33.38%；亚油酸乙酯0～21 d在5%～7%之间波动，后发酵第28天最高为12.36%。结合感官评价，确定出最佳后发酵期是4℃下发酵18 d，此时样品口感清爽、香气浓郁并适合饮用，且癸酸乙酯和月桂酸乙酯的含量达到峰值。
Abstract:Brown rice wine is a special fermented wine in China.It has a unique flavor that is derived from the raw materials and its brewing microorganisms.Postfermentation of microorganisms has a decisive influence on the final product quality at low-temperature.This paper mainly uses high-throughput sequencing technology and gas chromatography-mass spectrometry（GC-MS）to analyze the changes of bacteria and flavor substances in the postfermentation period of brown rice wine，to determine the dominant bacteria species，main flavor substances and best postfermentation period.The results showed that，for fungi，Saccharomyces cerevisiae was the most dominant species throughout the postfermentation period（average abundance，93.90%）.The highest relative abundances of the other two fungi，the unclassified Pichia species and Mucor circulans were 11.47% and 8.32%，respectively.For bacteria，Lactobacillus casei and L.brevis were the dominant strains throughout the postfermentation period，and their relative abundances were 85.72% and 10.68%，respectively.Contaminated Pseudomonas campylobacter and Pseudomonas aeruginosa were found on the 7 d of postfermentation.However，the two contaminating bacteria show significant decrease during the subsequent postfermentation period.The volatile flavor substances comprised esters（11），alcohols（3），ketones（2）and phenol（1）.Among them，esters were the most abundant（up to 60% to 80%）and included ethyl palmitate，ethyl linoleate and ethyl oleate，followed by alcohols （15%-30%）comprising β-phenyl alcohol，n-decyl alcohol and 2-methyl-1-butanol.Ethyl palmitate content，which was the highest during postfermentation，first decreased and then increased:33.06% to 26.90% from 0-14 d，and 26.90% to 33.38% from 14 d-28 d.The ethyl linoleate content fluctuates between 5% and 7% from 0-21 d，and reached the highest value（12.36%)on day 28.Based on sensory evaluation，the 18th postfermentation day（at 4 ℃）is reasoned to be the best postfermentation time，when，the sample has a refreshing taste，strong aroma，and is suitable for drinking，while the ethyl caprate and ethyl laurate contents reach peak levels.
keywords: brown rice wine postfermentation high-throughput sequencing technology bacterial succession volatile flavor substances
文章编号：202115027 中图分类号： 文献标志码：
基金项目:长株潭国家自主创新示范区专项（2018XK2007）；湖南省大学生创新创业训练计划项目（S202010538080X）
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