Modulating Protein Glycation in Skim Milk Powder via Low Humidity Dry Heating to Improve Its Heat-Stabilizing...

Area of Science:

• Food Science
• Dairy Technology
• Protein Chemistry

Background:

• Skim milk powder (SMP) has limited heat stability, restricting its use in high-temperature food processing.
• Dry heating improves thermal resistance but can accelerate the Maillard reaction, negatively impacting protein quality, color, and solubility.

Purpose of the Study:

• To enhance the heat resistance of SMP using low relative humidity (<10% RH) dry heating.
• To modulate the Maillard reaction during dry heating to preserve protein quality and functional properties.
• To produce recombined filled evaporated milk (RFEM) emulsions with improved characteristics.

Main Methods:

• Skim milk powder (SMP) was dry heated at 80, 100, and 120 °C for various durations.
• The Maillard reaction progression was assessed by monitoring color, protein solubility (Lowry assay), hydroxymethylfurfural, protein carbonyls, and sulfhydryl group content.
• Heat stability of SMP-derived RFEM was evaluated by measuring particle size (D4,3) and consistency coefficient (K).

Main Results:

• Low RH dry heating retarded the advanced Maillard reaction, evidenced by minimal color development and preserved protein solubility (90-97%).
• Hydroxymethylfurfural and protein carbonyls increased moderately, while sulfhydryl content remained stable, indicating limited protein aggregation.
• Heat treatment at 120 °C for 10 min significantly improved RFEM heat stability, reducing D4,3 by 25-fold and K by 108-fold.

Conclusions:

• Dry heating SMP under low relative humidity is an effective strategy to enhance its heat stability and functional properties.
• This method successfully mitigates detrimental Maillard reaction products, preserving protein quality and solubility.
• The findings support the application of low RH dry heating for producing high-quality dairy ingredients and emulsions for high-temperature applications.