Role of Proteins on Formation, Drainage, and Stability of Liquid Food Foams

Foam is a high-volume fraction dispersion of gas into a liquid or a solid. It is important to understand the effect of formulation on shelf life and texture of food foams. The objective of this review is to elucidate mechanisms of formation and stability of foams and relate them to the formulations. Emulsifiers are important in foam formation, whereas proteins are generally preferred to provide long-term stability. Syneresis in foams is a precursor to their collapse in many instances. Intermolecular forces, conformation, and flexibility of proteins play an important role in foam stabilization. An adsorbed protein layer at air/water interfaces imparts interfacial rheology that is necessary to improve the shelf life of foam products. Wettability and spreading of food particles at the interface can stabilize or destabilize foams, depending on their properties. More studies are needed to fully understand the complex interplay of various mechanisms of destabilization in a real-food formulation.