Animal proteins are commonly used ingredients in prepared foods, due to their desirable functional characteristics. However, proteins from animal sources are considered a relatively expensive raw material, so the possibility of replacing them with less expensive plant proteins presents an opportunity for cost savings in the production of protein-containing foods. Yet, currently, there are few food products on the market in which animal proteins have been replaced by plant proteins. NIZO food research has investigated the possibilities for use of plant proteins and, as an example, has developed a plant-based mayonnaise with good sensory characteristics.
Plant Proteins and Mayonnaise as a Model
Texture and stability of emulsions are product characteristics in which proteins play an important role. Therefore, mayonnaise was chosen as a test product for the application of commercial plant proteins, as this product depends on both protein functions. Mayonnaise is an oil-in-water emulsion, with a fat content of approximately 75% (whole-fat mayonnaise). The structure consists of fat globules pressed closely together in a water suspension. The proteins and phospholipids from the egg normally stabilize the fat globules and keep the emulsion intact. The proteins form a layer around the fat globules and also form bridges to multiple fat globules, reinforcing the structure. This is sometimes called “bridging.” The phospholipids, such as lecithin, stabilize the emulsion through “Pickering” stabilization (particle stabilization), in which small particles (such as lecithin) adhere to the fat globules, forming a barrier that prevents them from combining or coalescing. [Editor’s note: A Pickering emulsion is one in which a solid particle, such as lecithin, colloidal silica and so on, adsorbs onto the interface between two phases.]