Determination of polysaccharide in Lycium barbarum L. extract powder containing malt dextrin

Objective To establish a method for determination of polysaccharide in Lycium barbarum L. extract powder containing with malt dextrin. Method Maltodextrin was treated with glucoamylase hydrolysis and ethanol precipitation successively;then the phenol-sulfuric acid method was used to determine the content of polysaccharide. The glucoamylase hydrolysis technolgy of malt dextrin was optimized,and the variation of polysaccharide content before and after hydrolysis,the difference of polysaccharide contents between direct determination and truth were compared. Morever,the hydrolysis effect of glucoamylase on Lycium barbarum L. was investigated. Results The optimum hydrolysis condition was:temperature 60℃,the ratio of enzyme to substrate 1 ∶5,hydrolysis time 30 min. The polysaccharide content determined directly was significantly higher than the real value(P0.01);the polysaccharide content determined after hydrolysis decreased significantly(P0.01)but showed no significant difference with the real value(P 0.05). Glucoamylase showed no hydrolysis effects on Lycium barbarum L. polysaccharide. Conclusion Glucoamylase hydrolysis can deplete the influence of malt dextrin on determination of polysaccharide in Lycium barbarum L. extract powder,the procedure is simple and effective.