Dynamic Mechanical Analysis as a Complementary Technique for Stickiness Determination in Model Whey Protein Powders

Area of Science:

• Food Science
• Materials Science
• Polymer Science

Background:

• Whey protein concentrate (WPC) powders are widely used in food products.
• Understanding the stickiness and glass transition of WPC is crucial for processing and storage.
• Current methods for characterizing these properties may have limitations.

Purpose of the Study:

• To compare Dynamic Mechanical Analysis (DMA) with fluidization and Differential Scanning Calorimetry (DSC) for determining stickiness and glass transition temperatures in WPC powders.
• To investigate the influence of varying protein content on these properties.
• To assess the potential of DMA as a complementary technique for characterizing dairy powder stickiness.

Main Methods:

• Model WPC powders with different protein concentrations (20%, 35%, 50%, 65%) were analyzed.
• Dynamic Mechanical Analysis (DMA) was used to determine α-relaxation temperatures (Tα) from storage and loss moduli.
• Glass transition temperatures (Tg) were measured using Differential Scanning Calorimetry (DSC).
• Stickiness behavior was characterized using a fluidization technique.

Main Results:

• For lower protein WPC (20% and 35%), DMA Tα onset (storage modulus) correlated well with fluidization results.
• For higher protein WPC (50% and 65%), fluidization results aligned better with DMA Tα peak (loss modulus).
• This indicates that the relationship between DMA and stickiness is dependent on protein content.

Conclusions:

• DMA is a promising technique to complement stickiness characterization of dairy powders.
• DMA provides insights into the mechanisms underlying powder stickiness.
• The choice of DMA parameter (Tα onset vs. Tα peak) for correlating with stickiness depends on the protein content of the WPC.