Nutritionally valuable proteins from seafood side streams

Abstract: Availability of nutritive proteins is becoming a problem all over the world due to rising population. The situation demands exploration of novel sources of proteins to meet the demand. In this respect, seafood side streams can be a feedstock of acceptable and nutritionally valuable proteins. These side streams include (i) bycatch fish landed during commercial fishing that have poor food value, (ii) discards, and (iii) effluents generated during processing of commercially important fish and shellfish. It is well recognized that as high as 50 t0 60% of the commercially important fish and shellfish is discarded, which consist of shell, head, fileting frames, bones, viscera, fin, skin, roe, and others. Close to 8 million tons of protein-carrying waste crab, shrimp and lobster shells are produced globally. The solid discards, on a dry weight basis, may contain about 49 to 58% proteins. In addition, the voluminous amounts effluents released by the seafood industry including aquaculture is highly rich in proteins. While the meat mince from the bycatch can serve as raw material for protein-rich edible products, the process discards and effluents can be resources for nutritive proteins. These proteins can be recovered through biorefining employing upcoming, environmental-friendly, low-cost green processes. The up-coming non-thermal processes include pulsed electric field (PEF), high hydrostatic pressure (HHP), membrane technology, ultrasound-assisted extraction (UAE), and enzyme-assisted extraction. Cultivation of photosynthetic microalgae in nutrient media consisting of the side streams generates algal biomass, known as ‘single cell protein’ (SCP) from which nutritional proteins and also other valuable ingredients including carotenoids and oil can be recovered by novel extraction processes. A zero-waste marine bio-refinery approach has potentials for total recovery of the proteins and also other ingredients from the seafood side streams. The recovered proteins can have interesting applications as nutraceuticals and protein supplements. These aspects will be discussed