A review on fish peptides isolated from fish waste with their potent bioactivities

Fish processing unit establishment is now seeing an increasing trend of interest and subsequent activities. Thus, as a collateral the accumulation of greater amount of fish waste (head, skin, frames, visceral parts, and scales) and underutilized (non-edible) fish presents a greater opportunity for further utilization if not accounted for at the right time. Fish waste obtained during fish catch and processing account for about 70% and therefore, if not treated and discarded properly becomes a threat to environment. Currently, efforts have been made for utilization of these waste in different ways that includes production of saleable products, like animal feed, biogas; isolation of valuable bioactive biomolecules and fractions; separation and extraction of free amino acids, peptides, enzymes, fats and oils; collagen, gelatin, chitin, chitosan, vitamins, minerals, and polysaccharides. Isolated bioactive compounds and fractions further may be used in formulation and synthesis of pharmaceuticals, cosmetics, and nutraceuticals. This review precisely outlines the present understanding on fish waste as a source of high-value fish protein hydrolysates which can further be used for formulating different nutraceutical and therapeutic products such as antimicrobial, anticarcinogenic, antioxidant, and antihypertensive peptides, fish collagen and gelatin; and enzymes.