Classification, Composition, Extraction, Functional Modification and Application of Rice (Oryza sativa) Seed Protein: A Comprehensive Review

Food industry is actively searching for sustainable, economical, and high-quality protein source. Rice and its milling by-products prove to be cheap, high-quality sources of protein possessing immense nutritional and functional benefits. Rice seed protein (RSP) content and its quality, amino acid profile and fractions (i.e. albumin, globulins, prolamins and glutelins) have significant varietal influence. The functional properties (solubility, foaming properties, oil and water absorption, emulsification properties, etc.) depend on various factors such as extraction method, treatments, pH, concentration of salt & sugar in the foods. RSP has low solubility but various protein modification treatments have resulted in significant improvement in its solubility and other consumer preferential properties. RSP exhibits some therapeutic and nutraceutical properties such as hypoallergenic, antitumor, anti-atherosclerotic, antigenic properties with sound amino acid profile and substantial biological value. It can be used for biopolymer, bioactive compound delivery system, and effective natural antioxidant, treatment of hypertension and also for baby food formulations. This review discusses grain structure, composition, protein types, protein quality, extraction methods, functional properties and its modification. RSP is exceedingly comparable to existing protein sources such as soy, casein and fenugreek. Thus, RSP may be considered as a potential ingredient for food and allied industry.