Abstract:Aqueous extract of green tea was fermented with Lactobacillus plantarum ST isolated in the previous study.The fermentation conditions were optimized via single factor experiments and response surface methodology.The sensory score combined with antioxidant activity was used as the evaluation index.The antioxidant properties of fermented tea beverage were analyzed and compared with those of unfermented tea extract.In addition，the quality of fermented tea beverage during storage was evaluated.The optimal fermentation conditions were determined as L.plantarum ST inoculation amount of 7 lg（CFU/mL），sucrose addition amount of 6.6%，and fermentation at 38.7℃for 17 h.The beverage fermented under such conditions had the sensory score of 76.31.The fermented green tea beverage outperformed the unfermented green tea in terms of DPPH·and ABTS+·scavenging activities（P＜0.05）.After storage at 4 ℃ for 21 days，the fermented green tea beverage had the viable count of lactic acid bacteria over 6 lg（CFU/mL），high concentrations of tea polyphenols and caffeine，strong of DPPH·and ABTS+·scavenging activities，and good flavor and taste.