METHOD OF PREPARING CHITOSAN-BASE SUBSTANCE FOR FOOD AND PHARMACEUTICAL INDUSTRY Russian patent published in 2001 - IPC

FIELD: biochemical technology. SUBSTANCE: invention relates to method of preparing gel-like substance for foodstuffs and curative-cosmetic agents based on chitosan and it can be used in medicine, cosmetics and food industry. Method involves preparing chitosan solution in hydrochloric or acetic acid. Then nondissolved particles are removed by filtration or precipitation. Chitosan is modified with acylating agent under alkaline condition at pH 7.0-9.0 and obtained pH-neutral substance is washed out. Dicarboxylic acid dichloroanhydride is used as an acylating agent. Reaction is carried out at 18-25 C up to gel-like product preparing. Weight ratio of dicarboxylic acid dichloroanhydride and chitosan = (1:5)-(1:25) as measured for dry weight. Chitosan-base substance is autoclaved or dried by lyophilization or organic acids or organic acids-containing products of microbiological synthesis are added to the substance. Method ensures to obtain the substance useful in food and pharmaceutical industry. EFFECT: improved method of preparing, retained active biological properties of chitosan. 4 cl, 3 tbl