Xác định điều kiện lên men và hoạt tính kháng oxy hóa của nước lên men trái trâm (Syzygium cumini L.)

Abstract

This study is aimed to determine determine conditions effecting fermentation process of Syzygium cumini L. using Saccharomyces cerevisiae TN4 strain. Design Expert 7.0 was used determine optimal factors including pH, o Brix and yeast cell density. The results indicated that, with pH 4.2, 24 o Brix and 6 x 10 6 cells/mL, the highest alcohol content reached 10.78% v/v. After 3 days of fermentation, the fermented product reached an alcohol content of 5.20% v/v, consistent with fermented juice product. Simultaneously, 11 herbal compounds have been identified through spectroscopic methods, including steroids, triterpenoids, phenols, tannins, flavonoids, quinones, saponins, antocyanins, glucose, carotenoids and alkaloids from initial juice and fermented juice product. The quantitative change of these compounds before and after fermentation is negligible. The total polyphenol content of Syzygium cumini juice is higher than fermented product, particularly 57.0 mgGAE/L and 55.0 mgGAE/L respectively. After fermentation, the reduction peroxide capacity of fermented juice reached an IC50 value at 8.56 μL/mL, which is higher than the Syzygium cumini juice (IC50 value at 12.23 μL/mL.), shows that the fermented product has better antioxidant resistance than the original Syzygium cumini juice.