Abstract:

The crude inulin was extracted from burdock by dual enzyme hydrolysis. Three enzymes of papain, plant protease and acid protease with high hydrolysis yields of inulin from burdock were selected in this study. The extraction yields of inulin from burdock were 8.83%, 8.67% and 8.21% by these three enzymes, respectively. A single-factor experiment for each enzyme was used to investigate the effect of pH, solid/liquid ratio, amount of enzyme, temperature and time on yields of inulin from burdock. The enzyme was intercombined and the optimum combination was papain and plant protease, which presented the yields of 11.43%. Lasyly single-factor experiment and orthogonal experimental design were employed to study the effect of enzyme usage, solid/liquid ratio, temperature, time and pH on extraction efficicency from burdock. The optimum extraction conditions for dual enzyme hydrolysis were 10% papain + 20% plant protease, solid/liquid ratio 1:15, 45 ℃, 8 h of nzymolysis (4 h+ 4 h) and pH 8. The extracts were then precipitated by ethanol, concentrated in vacuum and the crude inulin was acquired. The extraction yield of inulin was 13.41%. The contents of inulin and protein in this product were 67.86% and 1.32%, separately.

Key words: inulin, extraction, burdock, duel enzyme hydrolysis