Functional colloids from proteins and polysaccharides for food applications

Developing novel food structures is nowadays becoming an attractive technology for food product innovation because they can be used to control textural properties, oral processing and perception, as well as biofunctionality in the human body. Proteins and polysaccharides are among the most abundant natural raw materials that can be used for creating novel food structures owing to their supramolecular interactions driven by attractive or repulsive forces. These two classes of biopolymers can be used to create different types of colloidal systems with unique properties, such as nano- or microparticles, hydrogels, films, emulsions, oil-filled hydrogels, foams, and oleogels, to name a few. In this review, we discuss a range of functional colloids which can be fabricated by exploiting spontaneous interactions of proteins and polysaccharides. Besides, the fundamental theories of proteins and polysaccharides interactions that can affect the structural formation are described. Furthermore, potential food applications of some selective functional colloids are also discussed with illustrative examples. The synergistic interactions of proteins and polysaccharides in their mixed system and a more complex system where a hydrophobic phase is present, could be employed to obtain various colloidal structures with numerous promising applications in the food industry.