Saccharide Constituents and Contents of Whey Syrup Prepared by Immobilized β-Galactosidase

Abstract

Lactose hydrolyzed whey syrup was prepared by treating whey with a commercial immobilized β-galactosidase, Saccharide constituents and contents in the whey syrup were investigated. The saccharide constituents and contents were similarly different because of oligosaccharides production and hydrolysis during the reaction. Twenty min before the reaction, six kinds of saccharides were detected; from 20 to 60 min of the reaction, seven kinds of saccharides were detected; 90min after the reaction, five kinds of saccharides were detected by HPLC in the whey syrup. Mass spectrometric analysis revealed saccharides as lactose, glucose, galactose, and di-, tri-, tetra-, pentasaccharide. Because galactose content was always lower than that of glucose, oligosaccharides were assumed to be mainly formed from galactose. The maximum amount of the oligosaccharide production was obtained at 40 min of the reaction, by which time about 15.04% of total saccharides had been converted to various oligosaccharides. However, the produced oligosaccharides in the whey syrup were hydrolyzed as the reaction time was continually extended. Therefore, in order to produce a whey syrup with high content for oligosaccharide, the reaction should be stopped at an opportune period when the whey syrup is prepared by immobilized β-galactosidase.