Micellar Precipitation and Reverse Micelle Extraction of Plant Proteins

Abstract

Current food challenges have allowed the development of innovative technologies to supply the global protein demand. Plant-based proteins are the most convenient protein sources due to their techno-functional properties, such as solubility, viscosity, emulsification, and water and oil retention capacity. Isoelectric precipitation is the most popular method to produce protein concentrates/isolates; however, other technologies, such as micelle precipitation and reverse micelle extraction, are underutilized technologies in the protein ingredients industry, despite their multiple advantages over other techniques, such as low denaturation of native plant proteins. Micelles, as nano-structures, are formed by amphipathic molecules with the polar heads in contact with the surrounding solvent, whereby hydrophobic chains of the micelle orient themselves inward. Proteins can be recovered easily from water-matrixes during micelle formation and can be precipitated, purified, and processed for multiple purposes. Reverse micelles are nano-sized aggregates of surfactant molecules in nonpolar organic solvents, containing an inner core of water molecules. During reverse micelle extraction, the proteins are attracted into the inner water core of the reverse micelles and they can then be recovered. Despite the few studies available about these extraction processes, the literature supports the fact that micellar precipitation and reverse micelle extraction may represent economic alternatives to obtain proteins at an industrial scale from oilseeds, pseudocereals, cereals, and legumes, as well as unexplored non-animal food sources.