Abstract: In order to explore the possibility of lactic acid bacteria (LAB) for improving the smoking quality of tobacco, two strains of LAB (Lactobacillus plantarum L8 and L14) were isolated and identified from Douchi, a Chinese traditional fermented food. Using L8 and L14 for cut tobacco fermentation, sensory evaluation results indicated that the smoke of fermented cigarette was fine and smooth, with a reducing miscellaneous gas and offensive irritancy, an obvious acid fragrance, and a clean aftertaste. On the basis of sensory evaluation, the fermentation condition of strain was optimized by orthogonal experiment. The results showed that the optimal aroma-producing condition was as follows: the inoculum size of 1×10⁸ CFU·mL^-1, the fermentation temperature of 37 ℃, the bacteria age of 10 h, and the tobacco producing area of Baoshan, Yunnan. Using the cut tobacco of commercial cigarette (Yunyan Ziyun) as fermented material, the results of sensory evaluation proved again that L8 and L14 could improve significantly the smoking quality of tobacco. The main chemical compositions in the fermented cut tobacco became more harmonious. The contents of total acid (especially of acetic acid) and total aldehyde (particularly of 3-methyl butyral) were significantly increased and reduced, respectively. The above results showed that LAB have great potential in improving tobacco quality.

Key words: Lactobacillus plantarum, aging, tobacco quality, sensory evaluation, aroma component