Influence of mixed cultures of saccharomyces cerevisiae and acetobacter aceti for hydrolysis of tannins in the cabbage fermentation (brassica oleracea l.var.capitata)

This study aims to hydrolysis tannins contained in cabbage (Brassica oleracea L.var.capitata) using a mixture of S.cerevisiae and A.aceti cultures with submerged fermentation method. Determination of the best conditions for tannins hydrolysis carried out by stratified optimization with variation of the volume mixed inculums (5%, 10%, 15% and 20% (v/v) in 100 mL distilled water) and pH values (4, 5, 6 and 7). Cabbage fermentation using a mixture of S. cerevisiae and A. aceti cultures with a ratio of 1:1 (v/v) and anaerobic incubation for 4 days at room temperature (25 ± 2 °C). The content of tannins before fermentation is 290.876 mg/100 g FW. After fermentation the tannins content decreased until the mixtures inoculum concentration was 15% and increased at 20%. The increase of tannins content due to the presence of high acetic acid on the fermentation medium so can inhibit tannase enzyme activity. The optimum volume of mixed inoculums at 15% produced tannins in the filtrate of 227.342 mg/100 mL and 193.619 mg/100 g FW biomass. Hydrolisis tannins can be carried out in acidic conditions. The optimum pH value at pH 4 produces tannins of 107.742 mg/100 g FW in biomass. Hydrolysis tannnins can be catalyzed by tannase produced from S.cerevisiae and acetic acid by A.aceti.