CHEMICAL AND NUTRITIONAL PROPERTIES OF PACIFIC OCEAN PERCH (SEBASTES ALUTUS) WHOLE FISH AND BY-PRODUCTS

There is a growing interest in developing either food or feed ingredients from the large volumes of Pacific Ocean perch (POP) by-products produced in Alaska. Determining the chemical composition of POP by-products is fundamental for developing novel ingredients using these materials. The objective of this study was to chemically characterize POP and its by-products. Triplicate samples of fresh POP whole fish, heads, frames and viscera were obtained from a commercial seafood processor in Alaska, and each replicate sample was individually analyzed for moisture, lipid, protein, ash, amino acid and mineral contents, fatty acid profile, lipid classes, pH, protein solubility, color, volatile amines and sodium dodecyl sulfate polyacrylamide gel electrophoresis of the proteins. The lipid and protein contents of the POP samples were 7.8 and 17.9% for whole fish, 10.5 and 15.2% for frames, 9.3 and 14.9% for heads, and 13.5 and 11.3% for viscera, respectively. Frames, heads and whole fish had ash values of 6.0, 6.7 and 4.3%, respectively. From the amino acid profiles, the values for lysine ranged from a low value of 7.3% for heads to a high value of 8.3% of total amino acids for frames. Methionine values ranged from 3.2 to 3.4% for all tissues. Frames and heads had high values for calcium and phosphorus, while viscera had the highest levels of iron. The analysis of fatty acids indicated high levels of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) with EPA/DHA ratios of approximately 2 for all tissues. Results indicated that the protein fraction of POP by-products was of high quality, and its lipids were a valuable source of omega-3 fatty acids.