Abstract: Purple potatoes from Dazhou, Sichuan province were used as raw material to ferment purple potato wine and the optimization of fermentation conditions was investigated by single factor experiments and response surface methodology. Gelatinized purple sweet potatoes were beaten into a slurry, liquified for 2.5 h with 0.15% α-amylase at 65 ℃ and pH 6.5, saccharified for 2.5 h with 0.15% glucoamylase at 60 ℃ and pH 4.0, and fermented for 7 days with 0.0845% Angel alcohol active dry yeast at 20.72 ℃ and pH 3.355. As a result, a novel purple potato wine of approximately 10°with a yield of 126.3% was obtained.

Key words: purple potato, purple potato wine, response surface methodology, saccharification, hydrolysis, fermentation