Milk powders ageing: effect on physical and functional properties

Area of Science:

• Food Science
• Materials Science
• Physical Chemistry

Background:

• Milk powders are valued food ingredients due to milk proteins' functional properties.
• Physicochemical damage during storage significantly impacts milk powder quality.
• Lactose glass transition is a key factor influencing these storage damages.

Purpose of the Study:

• To investigate the physicochemical damages in milk powders during storage.
• To understand the impact of lactose crystallization and protein denaturation on powder properties.
• To identify factors affecting milk powder quality degradation.

Main Methods:

• Analysis of changes in microstructure and chemical composition of powder particles.
• Assessment of physical properties like flowability, density, and caking.
• Evaluation of functional properties including solubility, emulsifying, and foaming capabilities.
• Consideration of storage conditions (temperature, humidity) and time.

Main Results:

• Lactose crystallization alters particle surface, decreasing flowability.
• Protein structure destabilization and unfolding damage solubility and functional properties.
• Particle collapse and caking reduce physical properties.
• Maillard and enzymatic reactions during ageing further impair solubility, emulsifying, and foaming properties.

Conclusions:

• Storage conditions and time significantly influence milk powder quality.
• Lactose crystallization and protein denaturation are primary causes of functional property loss.
• Understanding these mechanisms is crucial for maintaining milk powder quality and functionality.