A New Isolation Method of Caseinoglycopeptide from Sweet Cheese Whey

Abstract

Caseinoglycopeptides were isolated from sweet cheese whey by alcohol precipitation and ion exchange chromatography after heat coagulation of whey protein. The most successful method for obtaining the highest yield was by heating 10% (wt/vol) whey solution at pH 6.0 for 1 h, followed by precipitation with cold ethyl alcohol (50% vol/vol). The caseinoglycopeptide was fractionated into sialo- and asialo-caseinoglycopeptides by peanut (Arachis hypogoea) lectin-affinity chromatography. Caseinoglycopeptides exhibited five peaks on reverse-phase HPLC, which were divided into the first peak of an asialo-caseinoglycopeptide and sialo-caseinoglycopeptide in the following four peaks. The ratio of asialo-caseinoglycopeptide in whole caseinoglycopeptide is approximately 10%. Asialo-caseinoglycopeptide also could be prepared from cheese whey acidified to pH 3.0 and heated for 1 h at 98°C. Sialic acid in caseinoglycopeptide was completely released by this treatment. The yield of caseinoglycopeptide was approximately 1.1 g from 100 g of cheese whey powder. © 1991, American Dairy Science Association. All rights reserved.