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United States Department of Agriculture

Agricultural Research Service

Research Project: CONVERTING ALASKA FISH BY-PRODUCTS INTO VALUE ADDED INGREDIENTS AND PRODUCTS Title: Composition of Heads and Livers of Yelloweye Rockfish (Sebastes ruberrimus) Harvested in Alaska

Authors
item Oliveira, A.C.M. - UNIVERSITY OF ALASKA
item Bechtel, Peter
item Morey, A. - UNIVERSITY OF ALASKA
item Demir, N. - UNIVERSITY OF ALASKA

Submitted to: Journal of Aquatic Food Product Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: February 18, 2008
Publication Date: January 20, 2009
Citation: Oliveira, A., Bechtel, P.J., Morey, A., Demir, N. 2009. Composition of Heads and Livers of Yelloweye Rockfish (Sebastes ruberrimus) Harvested in Alaska. Journal of Aquatic Food Product Technology. 18:53-66.

Interpretive Summary: Yelloweye rockfish are a highly prized species in both commercial and recreational Alaska fisheries. Yearly catches of all rockfish is approximately 50,000 mt worth approximately 11 million dollars. Fish processing yields for Yelloweye rockfish are relatively low, but by-product volume can be up to 77% of whole fish weight. The objective of this research was to characterize yields and determine proximate composition, fatty acid (FA) and amino acid profiles, lipid classes, cholesterol content, and mineral composition of two of the major Yelloweye rockfish by-products, heads and livers. Yelloweye rockfish heads were the major by-product representing 42% of the total fish weight, and liver 2% of the total weight. Livers contained high levels of lipids (28.5%) but were of small size, while lipid content of heads was 7.5%. Recovered oils were of good quality being predominantly triacylglycerides. Oils were similar in many aspects to oils from other demersal cold water marine finfish and were rich in omega-3 and omega-9 FA, and low in omega-6 FA. Protein content in heads and livers were 16% and 11.5%, respectively. Amino acid analysis of the livers by-products revealed that the protein was of high quality and the mineral profile of heads was typical of livers from cold water marine fish. Overall, results indicated that YER by-products can be utilized for the production of high quality specialty ingredients that can be used as food and feed components or further purified for other uses.

Technical Abstract: Due to their large size and fillet quality, yelloweye rockfish (YER) are a highly prized species in both commercial and recreational Alaska fisheries. Processing yields for YER are relatively low, thus by-product volume is significant at up to 77% of whole fish weight (WFW). The objective of this research was to characterize yields and determine proximate composition, fatty acid (FA) and amino acid profiles, lipid classes, cholesterol content, and mineral composition of YER heads and livers. Heads of YER were the major by-product constituting 42% of WFW. YER livers made up only 2% of WFW. Livers contained high levels of lipids (28.5%) but were of small size, while lipid content of heads was 7.5%. Recovered oils were of high quality being predominantly triacylglycerides. Oils were similar in many aspects to oils from other demersal cold water marine finfish and were rich in omega-3 and omega-9 FA, and low in omega-6 FA. Protein content in heads and livers were 16% and 11.5%, respectively. Amino acid analysis of these by-products revealed that the liver protein was of high quality and the mineral profile of heads was similar to values for liver obtained from other cold water marine species. Overall, results indicated that YER by-products can be utilized for the production of good quality specialty ingredients that can be used as food and feed components.

Last Modified: 10/30/2014
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