红茶菌发酵液中多糖提取及测定条件优化

Optimization of extracting and determining conditions of polysaccharides in Kombucha

采用乙醇沉淀法提取红茶菌粗多糖.结果表明,当乙醇终浓度为90%(V/V)时,粗多糖得率为6.1 g.L-1发酵液;并从检测波长、浓硫酸和苯酚用量、显色温度和时间等方面对苯酚-硫酸法进行优化,优化后的苯酚-硫酸法测定条件为苯酚用量1 mL、浓硫酸用量4 mL,60℃显色15 min,检测波长484 nm.该方法显色稳定,重现性好,平均加样回收率R=85.70%,RSD=1.65%(n=5).

The polysaccharides in Kombucha were extracted by ethanol precipitation,and 6.1 g crude polysaccharides per litre fermentation broth were obtained when the ethanol final concentration was 90%（V/V）.The determining conditions of phenol-sulfuric acid method were optimized,and the optimal conditions were as follow： the amount of phenol and sulfuric acid was 1mL and 4mL respectively,temperature and time for color development was 60℃ and 15 min respectively,and detecting wavelength was 484 nm.The results showed that the optimized method was stable and had good reproducibility. The average recovery rate of sample was 85.70%, and RSD = 1.65% （n = 5）.