Lipid oxidation in sorted herring (Clupea harengus) filleting co-products from two seasons and its relationship to composition

Lipid oxidation in ice-stored sorted herring fractions (head, backbone, viscera + belly flap, tail, fillet) from spring and fall, and its association with endogenous prooxidants, antioxidants and lipid substrates were investigated. Peroxide value (PV) and thiobarbituric acid reactive substances (TBARS) had increased significantly in all fractions after 1 day, but for both seasons, the most rapid PV and TBARS development occurred in head, which also had highest hemoglobin (Hb) levels and lipoxygenases (LOX) activity. Viscera + belly flap was overall the most stable part, and also had the highest alpha-tocopherol content. Pearson correlation analyses across all five fractions confirmed a significant impact of Hb, LOX and alpha-tocopherol on the lipid oxidation susceptibility, while content of total iron, copper, lipids or polyunsaturated fatty acids provided no significant correlation. Overall, the study showed which pro-oxidants that should be inhibited or removed to succeed with value adding of herring filleting co-products and the fillet itself.

Automated summary

The study revealed that the head of herring showed the fastest lipid oxidation development, while the viscera + belly flap was the most stable part with the highest alpha-tocopherol content. Lipid oxidation susceptibility was significantly influenced by hemoglobin, lipoxygenases, and alpha-tocopherol, with no significant correlation found with total iron, copper, lipids, or polyunsaturated fatty acids.