Submitted to: Fisheries
Publication Type: Proceedings
Publication Acceptance Date: February 23, 2003
Publication Date: N/A
Technical Abstract: The Alaska fishery for Pacific Cod (Gadus macrocephalus) generates over 100,000 mt of fish processing byproducts per year. These byproducts come from human food processing lines and can easily be maintained as separate components. The byproducts can be used as sources of animal feeds and human foods. The objective of this study was to evaluate some of the properties of Pacific Cod byproducts. Three sets of cod samples were obtained on separate days from commercial fish processing plants and included; whole fish, heads, viscera, frames, fillets, and skins which were then prepared, and frozen at -80 C. Samples were analyzed for connective tissue content (AOAC), amino acid content, pepsin digestibility and estimated rat protein efficiency ratio (PRE) was calculated. Data was analyzed using ANOVA and the Duncan post hoc test with differences reported at (p<0.05). The average connective tissue content of the whole fish, heads, viscera, frames, fillets and skins was 5.7%, 13.2%, 5.0%, 10.6%, 1.6% and 42.6%, respectively. Whole fish and viscera were similar as were heads and frames (p>0.05), but fillet and skin were each different (p<0.05) from all other byproducts. The percent pepsin digestible protein ranged from 96-99% for 0.2% pepsin and 92-99% for 0.002% pepsin, indicating very digestible protein. The calculated rat PER values were 3.0, 2.9, 3.0, 2.9, 2.2 and 3.1 for whole fish, heads, viscera, frames skin and fillet, respectively. The connective tissue content of protein from cod byproducts fell into four general categories which were skin; fillet; viscera and whole fish; and heads and frames. All fish byproduct protein was readily digested by pepsin. These properties are of importance in devising feed ingredients and protein concentrates from cod processing byproducts.