Determination of Milk Proteins by Capillary Electrophoresis

Abstract

Abstract The potential utility of capillary electrophoresis (CE) for routine determination of milk protein is established. Proteins in cow's milk can be determined by CE in 10 min with high separation efficiency. The major protein components of milk are well-separated and identified. Separations of milk proteins are achieved reliably and reproducibly in an untreated fused-silica column of 21 µm id x 23- 25 cm. Fresh homogenized, low-fat, and nonfat milk show almost identical contents of each protein species; dry milk has a substantially reduced amount of whey proteins, especially oc-lactalbumin. Extensive degradation of whey proteins is evident from a reconstituted dry milk, which may be used to differentiate dry from fresh milk. By using the ratio of β-casein to α-lactalbumin, the adulteration of fresh milk with 25% or more of dry milk could easily be detected.