Composition of Heads and Livers of Yelloweye Rockfish (Sebastes ruberrimus) Harvested in Alaska

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, fatly acid (FA) and amino acid profiles, lipid classes, cholesterol content, and mineral composition of YER beads and livers. Heads of YER were the major by-product constituting 4296 of WFW. YER livers made lip only 2916 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 triacylglycerols. 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 beads and livers were 16% and 11.5%, respectively. Amino acid analysis revealed that the liver protein was of high quality. Mineral profile of livers was similar to values obtained from liver tissue 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.