初始含水率和菌群演替在雪茄烟叶发酵产香中的作用

The Roles of Initial Moisture Content and Microbial Succession in Aroma Production During the Cigar Tobacco Leaf Fermentation

以雪茄CX-14烟叶为材料,研究了初始含水率(30%、34%、38%)对雪茄烟叶发酵产香的影响,并通过宏基因组测序技术明确了雪茄烟叶的菌群结构及功能基因变化,分析了优势菌属在发酵过程中的贡献度,探明了菌群演替与雪茄烟叶香气产量变化的相关规律。结果表明:当雪茄烟叶含水率回潮至34%时,发酵后的苯丙氨酸转化产物、类胡萝卜素降解产物、西柏烷类降解产物、棕色化反应产物含量和香气总量分别比发酵前提高了77.2%、167.1%、28.6%、51.5%和169.3%,香气总量分别比30%和38%含水率组提高了26.6%和21.7%;通过宏基因组学分析,发酵后葡萄球菌属(Staphylococcus)丰度占比高达87.8%,是绝对优势菌属,而且其对发酵过程中的次生代谢物生物合成、ABC转运蛋白、氨基酸生物合成等代谢过程的贡献度超过了85%;经发酵菌属与烟叶香型相关性分析,发现类胡萝卜素转化产物是香型的主要呈现者,而且葡萄球菌菌属在香型节点最突出,是呈现香型的最大贡献者。综上所述,雪茄烟叶发酵前的最适含水率为34%,发酵过程中葡萄球菌属对雪茄烟叶发酵的香气产量有显著促进作用。

The effects of initial moisture content(30%,34% and 38%) on the fermentation aroma production of cigar tobacco leaves were investigated using cigar CX-14 leaves as materials.The changes in the bacterial colony structure and functional genes of cigar tobacco leaves were clarified by macro-genome sequencing technology,and the contribution of dominant genera in the fermentation process was analyzed to investigate the correlation law between the bacterial colony succession and the changes in the aroma production of cigar tobacco leaves.The results showed that when the moisture content of cigar leaves regain to 34%,the contents of phenylalanine conversion products,carotenoid degradation products,cembratriendid degradation products,browning reaction products and total aroma of the fermented cigar tobacco leaves were increased by 77.2%,167.1%,28.6%,51.5% and 169.3% compared with those of the prefermentation group,and the total aroma of the fermented cigar tobacco leaves was increased by 26.6% and 21.7% compared with that of the 30% and 38% moisture groups respectively;through macro-genomics analysis,the abundance of Staphylococcus accounted for 87.8%after fermentation,which was the absolute dominant genus,and its contribution to the metabolic processes such as secondary metabolite biosynthesis,ABC transporter protein,amino acid biosynthesis,and other metabolism processes in the process of fermentation was more than 85%.Through the correlation analysis between fermentation bacteria and aroma types of tobacco leaves,it was found that carotenoid conversion products were the main presenters of aroma types,and Staphylococcus was the most prominent in the aroma type node and the biggest contributor to aroma types.To sum up,the optimum moisture content of cigar tobacco leaves before fermentation is 34%,and Staphylococcus can significantly promote the aroma yield of cigar tobacco leaves during fermentation.