A single emulsifier material is seldom sufficient to cater to the requirements of complex emulsion-based food formulations that have to function over a wide range of pH, ionic strength, storage time, and temperature. Food emulsions have to be designed to satisfy several requirements for use which could be achieved by combining the beneficial properties of multiple emulsifiers. The present article reviews novel biological materials that are used to design oil-in-water (o/w) emulsions. More specifically, the major focus is to discuss (o/w) interfaces stabilized by multiple biopolymers. Prevalent ways by which two or more emulsifiers could be combined is by (i) forming multi-layered emulsions and (ii) conjugation of two compounds of beneficial traits. Multilayer emulsions make use of a combination of protein, phospholipids, and carbohydrates to stabilize (o/w) interfaces. On the other hand, covalent bonding between a protein and polysaccharide is induced to form a single entity known as conjugate that is superior to the individual biopolymers in terms of emulsion stability. Therefore, properties required to maintain emulsion stability such as surface activity, solubility, steric and electrostatic repulsion, and antioxidant effects from two different hydrocolloids could be integrated.
Keywords: Maillard reaction; Protein–polysaccharide; conjugates; layer-by-layer electrostatic deposition; secondary emulsion; tertiary emulsion.