The effect of combined traditional and novel treatments on oxidative status of dolphinfish ( Coryphaena hippurus ) and sardine ( Sardina pilchardus ) muscle lipids

Fish is rich in polyunsaturated fatty acids with beneficial effects on human health; however, these lipids are very sensitive to auto-oxidation reactions, leading to loss of nutritional and sensory quality. The effect of traditional (brining, smoking) and novel (addition of polyphenolic extracts, high pressure) preservation processes on the antioxidant/oxidative status of muscle lipids from dolphinfish and sardine was studied. Brining with oregano or rosemary aqueous extracts, as well as smoking, gave rise to deposition of phenolic compounds (9–42, 1.5–4.5 and 0.4–2.3 µg phenol/g for smoked, oregano-brined and rosemary-brined samples, respectively) in the muscle of both fish species. The antioxidant activity, as measured by ferric reducing ability, was also improved after brining with antioxidant extracts or smoking, results ranging from 8.9 to 82 mM FeSO₄ · 7H₂O equivalents/mg muscle depending on the treatment and the fish species. Consequently, fish lipid oxidation (as measured by thiobarbituric acid reactive substances) derived from brining and pressurizing, applied alone or in combination, was reduced between 6.6 and 69.8% depending on the treatment and the fish species. The combination of brining with oregano extract and light smoking showed an additional antioxidant effect, as compared with that obtained by smoking, on reducing sardine lipid oxidation derived from brining and pressurizing.