Coconut protein: an underutilized source of sustainable and functional protein for human nutrition

Coconut oil cake and meal generated during oil and milk processing contain significant quantity of high-quality proteins. Compared to other plant proteins, coconut proteins contain higher ratio of essential amino acids, better digestibility, and demonstrate versatile functionality in food matrices. However, they are seldom extracted at industrial scale and used in food formulations. This study evaluates the critical linkage between the extraction methods, protein structure, nutritional quality, functional properties, allergenicity, and their suitability for food applications. Conventional extraction techniques such as alkaline extraction and isoelectric precipitation are assessed alongside emerging techniques, such as membrane-based separations, enzyme, microwave and ultrasound-assisted extractions, with emphasis on the protein yield, structural integrity, and functional properties. Structure-function relationship governing solubility, thermal stability, gelation, interfacial, rheological, oil and water binding properties are critically analyzed, particularly for the predominant globulin fractions. The generation of bioactive peptides during enzymatic hydrolysis and their relevance in functional food are also examined. Strategies to improve functionality, including deamidation, protein-polysaccharide conjugation and amino acid-mediated modulation of protein-protein interactions, are discussed. Process scale-up and limited knowledge on value chain are the key challenges limiting the commercialization of coconut proteins. The work outlines directions for future research and industrial applications of coconut proteins.