Chemical Characteristics of Bovine Casein Micelles Fractionated by Size on CPG-10/3000 Chromatography

Abstract

Bovine casein micelles were fractionated on controlled pore granule (CPG-10/3000) chromatography by size and the chemical properties of the fractionated micelles were compared. The results indicated the presence of two types of micelles distinguishable as large and small micelles. In skim milk, 72.7% of casein was calculated to be in the form of small micelles, 13.6% in the form of large micelles and 13.8% in non-micellar casein form.The αs1-casein content decreased, but β- and κ-casein content increased as the micelle size became smaller. κ-Casein in large micelles had a much higher sialic acid content than in small micelles. It was found that this difference in sialic acid content was due to the presence of non-glycosylated κ-casein in small micelles. In large micelles, non-glycosylated κ-casein was almost undetectable.The addition of wheat germ lectin to micelles resulted in the formation of aggregates through intermicellar bridges between the carbohydrate chains of κ-casein located on the surface of t...