Revalorization of fish viscera as a sustainable source of proteins, lipids and polysaccharides in the food industry

Fish viscera, a fish processing by-product, is currently underutilized, despite its complex composition of high value-added components, such as proteins, lipids, and polysaccharides. This work explores the potential for revalorizing fish viscera as a sustainable source of proteins, lipids and polysaccharides in the food industry. Furthermore, their potential food applications and future perspectives are discussed. Fish viscera, constituting 12–18% of the total fish weight, is abundant in proteins, lipids, and polysaccharides. Protein hydrolysates derived from fish viscera exhibit diverse bioactivities, such as antioxidant, ACE-inhibitory, and antibacterial activities. Various enzymes with high stability properties can be extracted from fish viscera. Moreover, fish viscera-derived lipids are abundant in saturated/unsaturated fatty acids and phospholipids, which can exhibit excellent bioactivities such as immune regulatory, anti-inflammatory, lipid metabolism-regulatory and anti-tumor activities. Additionally, polysaccharides present in fish viscera display anticoagulant and antithrombotic activities. Overall, fish viscera have great potential as a good source of proteins, lipids and polysaccharides.