Abstract: Fermentation of tobacco leaves plays a key role in cigar quality and special favor. This paper studied the microbial diversity of tobacco leaves of two cultivars at different fermentation stages and the variation of three hydrolytic enzymes (protease, amylase and pectinase). It was found that the microbial floras were dynamic during the fermentation process. The microbial community of sample 1 was dominated by Staphylococcus at the early stage and changed to Enterobacter, Pseudomonas, and Brevibacterium at the end, while sample 2 had Staphylococcus and Tetragenococcus as the predominant species over the whole process. The enzyme activities changed a lot between cultivars and during the fermentation. For sample 1, the protease and amylase activities were maximal (165.95 U·g-1 and 0.34 U·g-1, respectively) at the end of fermentation, while the highest pectinase activity (1.30 U·g-1) was detected at the beginning. The protease activity (121.57 U·g-1) of sample 2 was the highest at the end, but lower than that of sample 1; and the pectinase and amylase activities in the middle reached to the peak,1.60 and 0.38 U·g-1, respectively, which were more than that of sample 1. Moreover, the pH of sample 1 changed significantly over the whole fermentation process, and changed to alkaline (pH 7.6) in the middle stage; and the pH of sample 2 changed little and kept acidic in three fermentation stages.

Key words: cigar, fermentation, microbial diversity, enzyme activity, pH

摘要： 烟叶原料发酵是决定雪茄品质与风味的关键因素之一，研究了雪茄烟叶不同发酵阶段的微生物多样性及蛋白酶、淀粉酶、果胶酶的变化规律。结果表明，不同发酵阶段微生物菌群呈动态变化，样品1在发酵起始阶段以葡萄球菌属为优势菌，结束则以肠杆菌属、假单胞菌属、短杆菌属为优势菌；而样品2在发酵过程中主要以葡萄球菌和四联球菌为优势菌。不同发酵阶段酶活性变化规律具有一定差异性：样品1蛋白酶(165.95 U·g^-1)与淀粉酶(0.34 U·g^-1)在发酵结束活性较强，果胶酶活性(1.30 U·g^-1)在发酵起始较强；样品2蛋白酶活性(121.57 U·g^-1)发酵结束活性较强；果胶酶活性(1.60 U·g^-1)与淀粉酶活性(0.38 U·g^-1)在发酵中期活性较强。样品1雪茄原料在三个不同发酵阶段pH变化较为明显，在发酵中期pH为7.6，呈碱性；样品2雪茄原料在不同发酵阶段pH变化较小，整个发酵阶段pH呈酸性。

关键词: 雪茄, 发酵, 微生物多样性, 酶活, pH