ALASKA FISH PROCESSING BYPRODUCTSTitle: Nutritional and chemical composition of by-product fractions produced from wet reduction of individual red salmon (Oncorhynchus nerka) heads and viscera
Submitted to: Journal of Aquatic Food Product Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: December 30, 2010
Publication Date: April 20, 2011
Citation: Wu, T.H., Nigg, J.D., Stine, J.J., Bechtel, P.J. 2011. Nutritional and chemical composition of by-product fractions produced from wet reduction of individual red salmon (Oncorhynchus nerka) heads and viscera. Journal of Aquatic Food Product Technology. 20(2):183-195.
Interpretive Summary: Individual by-products can be directly collected off the processing lines for utilization into feed. Here individual heads and viscera from red salmon were collected and processed into fish meals. During the processing of the by-product into fish meal three fractions are generated (cake, stickwater and oil). These factions were evaluated between the head and viscera meals produced. The most significant difference was noted in the oil produced from viscera which contained an increase of 3000 folds in concentration of vitamin A. Other nutritional and chemical differences were also noted between the two individual by-products.
There is growing interest for fish meals and oils made from utilizing different fish by-products (heads, viscera, frames, etc.) that come directly from the commercial processing line. The major components of fish processing waste from salmon filleting operations are heads and viscera. In order to maximize the utilization of these individual by-products, the different fractions were evaluated. Analysis of essential amino acids in fish meal showed significant differences in all essential amino acids except lysine. Differences were also noted in the levels of minerals, fatty acid method esters, biogenic amines and fat soluble vitamins. The largest difference observed was in the level of retinol in the oil extracted from heads (8.9±1.0 ug/g oil) and viscera (26900±380 (ug/g oil). Heads processing resulted in more lipids and cake, while the majority of viscera became stickwater. Results suggest that the fish meal produced from different by-product parts can result in different nutritional value feed or food ingredients.