Abstract: Broken rice was processed by two-step method with alkali and enzymatic hydrolysis for preparing pure rice starch. The results indicated that the optimum process conditions to isolate rice starch and protein respectively by alkali are as follows: pH 11, 40 ℃, ratio of water to flour 8 and 120 min. Alcalase is used to purify rice starch with the conditions of enzymatic hydrolysis pH 9, 45 ℃, ratio of enzyme/protein 48 AU/kg and 60 min. Content of protein in rice starch decreases from 2.87% to 0.40%(dry).

Key words: rice starch, two-step method of alkali and enzymatic hydrolysis, alcalase