Classification of α-Lactalbumin and β-Lactoglobulin

α-Lactalbumin and β-Lactoglobulin are known as:

Correct Answer: Both Whey protein and Milk serum protein

α-Lactalbumin and β-Lactoglobulin are both Whey proteins and Milk serum proteins — these two terms are synonymous.

Milk Protein Classification

• Casein protein (80% of total milk N): Exists as calcium-caseinate-phosphate complex; responsible for white colour and viscosity of milk; types: α-casein, β-casein, γ-casein.
• Whey proteins / Milk serum proteins (20%):
  • α-Lactalbumin
  • β-Lactoglobulin

Key Differences

• Casein — present as colloidal suspension
• Whey proteins — present as colloidal solution
• Whey proteins are denatured by heat; casein is heat-stable
• Greenish-yellow colour of whey is due to Riboflavin, not whey protein itself