Abstract: Scallop gonads, a major by-product of scallop processing, have attracted considerable attention in recent years due to their high protein content. Scallop gonad protein isolates (SGPIs) and hydrolysates (SGHs)​ have been proven to possess excellent physicochemical and functional properties and can be used in constructing novel food delivery systems. This article systematically summarizes the structural characteristics and physicochemical properties of SGPIs and SGHs and reviews recent advances in the application of SGPIs and SGHs in food delivery systems. Research indicates that SGPIs contain all essential amino acids, and SGHs exhibit high similarity to SGPIs. Various physical treatments (e.g., isoelectric solubilization/precipitation, and ultrasound) and chemical treatments (e.g., polyphenols and polysaccharides) can significantly improve key functional properties of SGPIs and SGHs, including solubility, surface hydrophobicity, gelation properties, water/oil-holding capacities, emulsifying ability, foaming capacity, digestibility, and antioxidant activity. Due to their favorable interfacial and bioactive properties, SGPIs and SGHs have been applied in the development of food delivery systems such as composite gels, emulsions, and covalent complexes to enhance the stability and bioavailability of functional components (e.g., polyphenols and carotenoids). Covalent and non-covalent interactions (e.g., electrostatic interactions, hydrogen bonding, and hydrophobic interactions) play crucial roles in the formation of delivery systems and the encapsulation of functional substances. In summary, SGPIs and SGHs hold great promise as novel wall materials with broad applications in the food, pharmaceutical, and other industries.

Key words: scallop gonad protein isolates; scallop gonad hydrolysates; chemical structure; physicochemical properties; food delivery systems