Submitted to: Annual Meeting World Aquaculture Society
Publication Type: Proceedings
Publication Acceptance Date: March 1, 2004
Publication Date: March 1, 2004
Citation: Bechtel, P.J. 2004. Studies on nutritional properties of white fish processing byproducts: heads,frames,viscera, and skin.. Annual Meeting World Aquaculture Society.
The fisheries for Alaska pollock and Pacific cod annually generate over 700,000 mt and 100,000 mt of processing byproducts. These byproducts are easily maintained as separate components during fish processing which could then be used as raw materials for specialty feed and food ingredients. The objective of this study was to evaluate some of the nutritional properties of pollock and cod byproducts. Three sets of Alaska pollock (Theragra chalcogramma) and Pacific cod (Gadus macrocephalus) 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 meat procedure), amino acid profiles, pepsin digestibility and calculations of an estimated rat protein efficiency ratio (PRE). Data was analyzed using ANOVA and the Duncan post hoc test and differences reported (p<0.05). The connective tissue content of pollock and cod were determined for whole fish (6.8 % and 5.7 %), heads (9.8 % and 13.2 %), viscera (1.0 % and 5.0 %), frames (7.6 % and10.6 %), fillets (1.6 % and 1.6 %) and skins (45.5 % and 42.6 %), respectively. Between species only viscera connective tissue values were different (p<0.05). Percent pepsin digestible protein ranged from 92-99 % for all pollock and cod byproducts when using a standard 0.2 % pepsin solution. Calculated rat PER values derived from amino acid profiles of pollock and cod were determined for whole fish (3.0 and 3.0), heads (2.7 and 2.8), viscera (3.1 and 2.8), frames (2.9 and 2.9), skin (1.7 and 1.7) and fillet (3.1 and 3.1), respectively. Between species only viscera PER values were different (p<0.05). Common pollock and cod byproducts generally had similar chemical and nutritional values. These properties are of importance in developing feed and food ingredients and protein concentrates from pollock and cod processing byproducts.