Rapid Determination of Lactose and Its Hydrolyzates in Whey and Whey Permeate by High Performance Liquid Chromatography

Abstract

A rapid method is presented for the quantitative analysis of lactose, glucose, and galactose in whey and whey permeate by high performance liquid chromatography. Samples were prepared by heating to precipitate most proteins and by eluting through a Sep-Pak™ cartridge to remove lipids, chromophores, and residual proteins. Sugars were separated on an Altex μ-Spherogel Carbohydrate column and measured by a refractive index detector. Recovery of added carbohydrates averaged 98.0% for lactose and 101.5% for glucose and galactose. Coefficients of variation for recovery ranged from .27 to 3.20%. Reproducibility was demonstrated by our monitoring rate of enzymatic hydrolysis of lactose in whey permeate. Sample preparation time was 15 min; chromatographic separation was within 15 min. © 1984, American Dairy Science Association. All rights reserved.