Submitted to: Journal of Aquatic Food Product Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 6, 2003
Publication Date: January 1, 2004
Citation: Bechtel, P.J., Johnson, R. 2004. Nutritional properties of pollock, cod, and salmon processing byproducts. Journal of Aquatic Food Product Technology. Vol. 13(2) pages 125-142 (2004)
Interpretive Summary: The annual seafood harvest in Alaska is over two million metric tons and more than one million metric tons of fish processing byproducts are produced annually, the majority of which is not utilized. The three species from which the most byproducts are derived include Alaska pollock, Pacific cod and pink salmon. Major pollock and cod byproducts are heads, viscera, frames and skins. For pink and red salmon major byproducts are heads and viscera. In this paper the amino acid analysis, pepsin digestibility and mineral content of pollock, cod and salmon byproducts were determined. There were differences between many of the fish byproducts in terms of amino acid composition, mineral analysis, calculated rat protein efficiency ratio, and protein solubility. However all byproducts were found to have a high degree of pepsin digestibility. The results from this study identify important characteristics of individual fish byproduct components that could be used to create new products and feed ingredients.
When fish are processed for human consumption the common byproducts are heads, viscera, frames and skins which are often combined and made into fish mealS. It is possible to make feed ingredients out of the individual byproducts. Heads, viscera, frames, and skins were obtained from plants processing Alaska pollock(Theragra chalcogramma) and Pacific cod (Gadus macrocephalus); and heads, and viscera from pink salmon (Oncorhynchus gorbuscha). Essential amino acid concentrations were used for calculating rat protein efficiency ratio (PER) and resulted in high values for fillet (3.14), followed by whole fish, frames and viscera , heads and skin (1.66). All byproducts had greater that 90% pepsin digestibility except salmon viscera. Mineral content differences were detected. Percent soluble protein of pollock and salmon byproducts increased as pH increased from 5.4 to 7.1.