Abstract: The physico-chemical properties of chitosans have the correlationship with their functional properties. It has proved that chitosan has the potent hypocholesterolemic activity in vivo. In this paper, the effects of degree of deacetylation (DD) and viscosity-average molecular weight (Mv) of chitosan samples on their fat-binding, cholesterol-binding and bile salts-binding capacities were studied in vitro. Nine chitosan samples with different DD and Mv were prepared by chemical methods. The binding capacities of fat, cholesterol and bile salts were determined in the conditions simulating human gastrointestinal tract. The optimal additions of samples for binding assays are 120 mg fat-binding assay and 40 mg bile salts-binding, respectively. The fat-binding capacity ranges from 11～37.4 g fat/g chitosan higher than that of cellulose significantly and it increases with the increase of DD and Mv. The cholesterol-binding capacity does not show the regularity variation with the changes of the DD and Mv, but is affected by the diameter of the granule. The bile salts-binding capacity is 1.75～7.75 mg/g chitosan. The viscosity-average molecular weight affects the binding capacity greatly. Chitosan sample with highest molecular weight shows the best bile salts-binding capacity. The degree of deacetylation seems to have no effect on the bile salts-binding capacity. These results indicated that the physicochemical properties of chitosan affect its binding capacities and hypocholesterolemic and hypolipidemic activities.

Key words: chitosan, degree of deacetylation