Protein Ingredients in Low- and Intermediate-Moisture Systems

Protein ingredients are applied in a wide variety of food and nonfood products. Protein functionality in liquid systems is widely studied and well-understood, but this understanding is not directly translatable to low- and intermediate-moisture systems, such as powders and protein bars. The relatively low moisture content and water activity in such systems ensure that proteins are not fully hydrated and are packed much closer, and that some reactions, e.g., the Maillard reaction, occur more rapidly than in liquid systems. By carefully considering the low- or intermediate-moisture environment and how it affects protein interactions, understanding and controlling common industrial problems, such as the hardening of protein bars and the development of insolubility and discoloration in powders, can be achieved.