Role of β-glucan content, molecular weight and phytate in the bile acid binding of oat β-glucan.

There is controversy about the role of viscosity and co-migrating molecules on the bile acid binding of beta-glucan. Thus, this study aimed to investigate the impact of β-glucan molecular weight and the content of both β-glucan and phytate on the mobility of bile acids by modelling intestinal conditions in vitro. Two approaches were used to evaluate factors underlying this binding effect. The first studied bile acid binding capacity of soluble β-glucan using purified compounds. Viscosity of the β-glucan solution governed mainly the mobility of bile acid since both a decrease in β-glucan concentration and degradation of β-glucan by enzyme hydrolysis resulted in decreased binding. The second approach investigated the trapping of bile acids in the oat bran matrix. Results suggested trapping of bile acids by the β-glucan gel network. Additionally, hydrolysis of phytate was shown to increase bile acid binding, probably due to better extractability of β-glucan in this sample.