Color formation in dehydrated modified whey powder systems as affected by compression and T(g)

Area of Science:

• Food Science
• Dairy Chemistry
• Physical Chemistry

Background:

• The Maillard reaction is a key deteriorative process affecting dairy products like whey powders during storage.
• Understanding factors influencing the Maillard reaction is crucial for maintaining dairy product quality.

Purpose of the Study:

• To investigate the influence of physical matrix structure (porous vs. compressed) on the Maillard reaction in various whey powders.
• To examine the effect of storage temperature relative to the glass transition temperature (T(g)) on Maillard reaction kinetics.

Main Methods:

• Colorimetric measurements using a spectrocolorimeter to quantify browning.
• Thermal analyses (TGA) and differential scanning calorimetry (DSC) to study thermal properties and glass transition temperatures.
• Storage of whey powders (W, WRM, WPC, WPI) at selected temperatures in both porous and compressed states.

Main Results:

• Browning intensity followed the order: Sweet Whey (W) > Reduced Minerals Whey (WRM) > Whey Protein Concentrate (WPC) > Whey Protein Isolate (WPI).
• Compressed whey systems showed higher rates of browning and weight loss (attributed to nonenzymatic browning - NEB) compared to porous systems when stored below T(g).
• The rate of weight loss (k(w2) from TGA) correlated well with browning development, indicating water loss associated with NEB.

Conclusions:

• The physical structure of whey powders plays a significant role in modulating Maillard reaction rates.
• Mechanical compression enhances nonenzymatic browning in whey systems, particularly in the glassy state.
• As temperature increases relative to T(g), the influence of physical structure on reaction rates diminishes.