Abstract: Dietary fider was extracted from burdock hydrolyzed by enzymes in this study. The plant protease and glucoamylase were used to hydrolyze respectively protein and starch after pretreating burdock. The soluble dietary fiber was precipitated by using 95% ethanol and then washed by using ethanol and acetone to remove fat-soluble substances. After drying and ashing,the residue was purifed dietary fiber. The results showed that the optimal techological conditions for preparing burdock dietary fiber are as follows: plant protease amount 6%,glucoamylase 1.2%,pH 7.0,time 4 h and temperature 50℃. The yield of the burdock dietary fiber is 63.74%.

Key words: burdock, dietary fiber, plant protease, glucoamylase