ARS | Publication request: ALKALI EXTRACTED PROTEIN FRACTIONS FROM SALMON BYPRODUCTS

Submitted to: Journal of Food Science and Technology
Publication Type: Abstract Only
Publication Acceptance Date: March 15, 2005
Publication Date: N/A

Technical Abstract: From 1995-2000 the harvest of wild salmon (Oncorhynchus spp.) from Alaska waters averaged 364,000 mt. It has been estimated that the major byproducts available in Alaska from Pacific salmon processing include over 50,000 mt of salmon heads and 30,000 mt of viscera, of which much is under utilized. Soluble and insoluble fractions from salmon head and salmon viscera can be produced via alkali-aided extraction for use as functional animal feed ingredients. The objective of this study was to isolate both soluble and insoluble protein fractions from salmon byproducts and characterize the chemical and functional properties of the protein powders. Pink salmon (Oncorhynchus gorbuscha) viscera and red salmon (Oncorhynchus nerka) heads were used in this study. Pink salmon viscera (PV) and red salmon head (RH) samples were collected from a commercial processing plant and stored at –20oC until thawed for protein extraction. Triplicate samples of minced samples were diluted in deionized water (1:9), homogenized, solubilized at pH 11, soluble and insoluble fractions separated by centrifugation, and the soluble fraction precipitated at pH 5.5. The freeze-dried PV-soluble (PVS) and PV-insoluble (PVIS), RH-soluble (RHS), and RH-insoluble (RHIS) fractions were analyzed for proximate composition, TBA values, lipid classes and amino acid contents. Evaluations of functional properties included emulsion stability (ES), fat absorption, solubility and color. RHIS, PVIS, RHS, and PVS contained 50.7%, 69.4%, 80%, and 87.2% protein, respectively. Emulsion stability of RHS (79.5%) was greater than that of RHIS (73.1%), PVIS (61.1%) and PVS (57.1%). Both insoluble fractions (RHIS and PVIS) had higher fat adsorption values than PVS and RHS. All the salmon protein powders were white to lightly yellow and had desirable amino acid profiles. The soluble and insoluble fish protein isolates from red salmon head and pink salmon viscera have potential as functional protein ingredients.