Quantitative Determination of Oligosaccharides in Commercial Soybean Lecithin Products by High-Performance Liquid Chromatography

Abstract

A method to quantitatively determine the oligosaccharides in a commercial soybean lecithin product by high-performance liquid chromatography (HPLC) was studied. The lecithin product was dispersed in chloroform/methanol/water (10/8/9, v/v) containing an internal standard, and a portion of the water phase was injected onto the anion exchange HPLC column. Oligosaccharides were selectively monitored by a fluorescence detector after a post-column chemical reaction with arginine. This method was highly sensitive (<0.1μg) and also applicable for the determination of saccharide content in soybeans. By this method, we demonstrated that the oligosaccharides in the product were changed into fluorometrically undetectable components by a browning reaction, and that monosaccharides of soybean were not contained in the product.