Proteins and Co-products from Seafood Processing Discards: Their Recovery, Functional Properties and Applications

Abstract

Commercial processing of seafood results in enormous amounts of solid discards, offal or by-products. These discards, on dry weight basis, contain up to 60% proteins, consisting mostly of myofibrillar proteins, collagen, enzymes, and also soluble nitrogenous compounds. In view of their nutritional and functional values, there is a need for recovery of these proteins from the discards, which will help better utilization of harvested and farmed seafood besides reducing seafood-associated environmental problems. Iso-electric pH solubilization precipitation is a plausible method for the recovery of proteins from fishery discards. The recovered proteins are comparable with conventional surimi in gel forming and other functional properties. Other approaches for protein recovery include mechanical deboning of fish frames, development of weak acid-induced gels, protein dispersions, and treatment of the discards by proteolytic enzymes. This article discusses recovery of proteins, enzymes, protein hydrolyzates and peptides from seafood processing discards, their nutritional, bioactive and functional properties, as well as their food and nutraceutical applications.