Abstract:

The contents of theα -lactalbumin (α -Lac), β -lactoglobulin A (β -LgA) and β -lactoglobulin B (β-LgB) were determined by capillary electrophoresis in whey protein powder, bovine colostrum and raw milk from the local farm, infant formula of the same brand but for different age stages or of the same age stages from different plants and countries, liquid milk with different shelf-life, ultra-high temperature (UHT) milk and yogurt from different countries and domestic reconstituted milk. The contents of the above three proteins decreased in the order of whey protein powder, bovine colostrum and raw milk, and were negatively related to the shelf-life of milk and milk products. The content of α-Lac in most of the yogurts were higher than that in UHT milk. The contents of the α-Lac in infant formula increased with the age stage. Infant formula with the same age stages of different brands and countries had significant differences in the contents of α-Lac. The contents of α-Lac in imported formula were not always higher than those from domestic ones. The results provide a valuable asset for the analysis of true proteins in milk and milk products.

Key words: capillary electrophoresis, whey protein powder, bovine colostrum, raw milk, infant formula, ultrahigh temperature (UHT) milk, yogurt