Chapter 4: Flavor–Protein Binding on Flavor Delivery

A major consumer trend today is to increase the amount of protein in the diet. Flavoring foods containing proteins is problematic due to both weak (ionic, van der Waals, hydrogen bonding, etc.) and strong interactions (covalent bonds) that occur between flavoring components and proteins. Weak (aka reversible) bonds come to equilibrium, and thus, a flavor can often be reformulated to possibly compensate for this initial binding. Unfortunately, the loss of flavor components to covalent (aka irreversible) bonds with the protein does not come to any equilibrium but continues until all of the reactive sites (amino acids) in the protein have reacted with the flavoring or all of the reactive flavor components have been consumed. Various factors such as reaction components (flavor compounds and protein type), reaction environment (system pH, a_w, and presence of salts/solvents), and reaction conditions (thermal processing and storage temperature) all affect flavor–protein reactions. This chapter will discuss what has been learned about both the reversible and irreversible bond formation between flavorings and various proteins.