Physicochemical and Hypocholesterolemic Characterization of Oxidized Oat beta-Glucan

Abstract

2,2,6,6-Tetramethyl-1-piperidine oxoammonium ion (TEMPO)-mediated oxidation was applied to oat beta-glucans, and the physicochemical and hypocholesterolemic properties of the resulting derivatives were investigated. The C-13 NMR spectra revealed that C6 primary alcohol groups were selectively oxidized into carboxyl groups. The oxidized derivatives exhibited enhanced water solubility and improved in vitro bile acid binding capacity. When hypercholesterolemic rats were fed diets containing the oxidized beta-glucan, the levels of triglyceride, total cholesterol, LDL-C, and VLDL-C in the rats significantly decreased (p < 0.05), consequently improving the serum lipid profiles. Dietary supplementation with beta-glucans reduced also the total cholesterol level in liver. Furthermore, more fecal eliminations of total cholesterol and triglyceride were observed, which were favorably correlated to their reduced levels in the serum and liver. As a result, oxidized oat beta-glucan exhibits potential use as an active cholesterol-lowering ingredient.