Casein Micelle Structure and Properties

Casein Micelle Structure

• A casein micelle is a spherical, colloidal particle consisting of:
  • Casein proteins (αs1, αs2, β, and κ)
  • Calcium phosphate (CaP) nanoclusters
  • Water

Properties

• Diameter: 50-300 nm
• Molecular weight: 10^6 - 10^7 Da
• Negative charge: due to the presence of phosphate groups
• Hydrophilic and hydrophobic regions: allowing for interactions with both water and fat molecules

Formation

• CaP nanoclusters form in the presence of calcium ions
• Casein proteins bind to CaP nanoclusters through phosphate groups
• Hydrophobic regions of casein proteins interact to form a stable, spherical structure

Functions

• Stabilize milk fat globules: preventing them from coalescing and separating
• Regulate calcium and phosphate levels in milk
• Involved in cheese production: coagulation of casein micelles leads to curd formation

Types

• κ-Casein micelles: stabilize the micelle structure and interact with β-casein
• α-Casein micelles: more sensitive to calcium ions and pH changes

Importance in Dairy Industry

• Casein micelles play a crucial role in milk processing and cheese production
• Understanding their structure and properties is essential for optimizing dairy product quality and yield

Casein Micelle Structure

• A casein micelle is a spherical, colloidal particle composed of casein proteins (αs1, αs2, β, and κ), calcium phosphate (CaP) nanoclusters, and water.

Properties of Casein Micelles

• Diameter: 50-300 nm
• Molecular weight: 10^6 - 10^7 Da
• Possesses a negative charge due to the presence of phosphate groups
• Exhibits both hydrophilic and hydrophobic regions, enabling interactions with water and fat molecules

Formation of Casein Micelles

• Calcium phosphate (CaP) nanoclusters form in the presence of calcium ions
• Casein proteins bind to CaP nanoclusters through phosphate groups
• Hydrophobic regions of casein proteins interact to form a stable, spherical structure

Functions of Casein Micelles

• Stabilize milk fat globules, preventing coalescence and separation
• Regulate calcium and phosphate levels in milk
• Involved in cheese production, as coagulation of casein micelles leads to curd formation

Types of Casein Micelles

• κ-Casein micelles: stabilize the micelle structure and interact with β-casein
• α-Casein micelles: more sensitive to calcium ions and pH changes

Importance in Dairy Industry

• Casein micelles play a crucial role in milk processing and cheese production
• Understanding their structure and properties is essential for optimizing dairy product quality and yield