Fish protein hydrolysates: Proximate composition, amino acid composition, antioxidant activities and applications: A review.

The fish processing industry produces more than 60% by-products as waste, which includes skin, head,
viscera, trimmings, liver, frames, bones, and roes. These by-product wastes contain good amount of protein
rich material that are normally processed into low market-value products, such as animal feed, fish
meal and fertilizer. In view of utilizing these fish industry wastes, and for increasing the value to several
underutilised fish species, protein hydrolysates from fish proteins are being prepared by several researchers
all over the world. Fish protein hydrolysates are breakdown products of enzymatic conversion of fish
proteins into smaller peptides, which normally contain 2–20 amino acids. In recent years, fish protein
hydrolysates have attracted much attention of food biotechnologists due to the availability of large quantities
of raw material for the process, and presence of high protein content with good amino acid balance
and bioactive peptides (antioxidant, antihypertensive, immunomodulatory and antimicrobial peptides).