Galactosyl oligosaccharide purification by ethanol precipitation

Abstract

Galactosyl oligosaccharides (GOS) are prebiotics commonly manufactured by β-galactosidase conversion of lactose, producing a mixture containing GOS, lactose, glucose and galactose. Enrichment of GOS in this mixture adds value to the product. This study aimed to determine whether the addition of ethanol to aqueous saccharide solutions could be used to selectively precipitate and enrich GOS from a reaction mixture. High concentrations of ethanol (>70% v/v) were required to induce precipitation. The total saccharide concentration was a significant variable, with higher GOS enrichment occurring at lower total saccharide concentrations. Varying the temperature between 10 and 40 °C had less impact..