In vitro binding of bile acids and triglycerides by selected chitosan preparations and their physico-chemical properties

The selected 11 chitosan samples were evaluated for their fat- and bile acid-binding capacities, physico-chemical properties, and the correlations between each binding capacity and individual physico-chemical properties. The bile acid- and fat-binding capacities were estimated using in vitro assays, whereas the measured physico-chemical properties were deacetylation degree, swelling capacity, and solution viscosity. Chitosan samples might differ in their binding capacities against fat and/or individual bile acids. The bile acid-binding capacities were 0.20–0.61, 0.43–1.63, and 0.61–1.61 μmol/g chitosan for cholic, deoxycholic, and chenodeoxycholic acids, respectively. Stronger binding capacity of chitosan against a selected bile acid does not warrant greater binding capacity for other bile acid. The fat-binding capacity ranged from 1077–1239 g oil/g for the chitosan samples under the experimental conditions. No correlation was observed between any binding ability and individual physico-chemical properties, although the swelling capacity of chitosan was correlated to the solution viscosity (r=0.82r=0.82, P=0.02P=0.02) and deacetylation degree (r=-0.62r=-0.62, P=0.04P=0.04), indicating that none of the measured physico-chemical properties can be used to predict the fat- or bile acid-binding ability of chitosan.