Stabilizing Oils from Smoked Pink Salmon (Oncorhynchus gorbuscha)

Abstract

Smoking of meats and fish is one of the earliest preservation technologies developed by humans. In this study, the smoking process was evaluated as a method for reducing oxidation of pink salmon (Oncorhynchus gorbuscha) oils and also maintaining the quality of oil in aged fish prior to oil extraction. Salmon heads that were subjected to high temperatures (95 degrees C) during smoking unexpectedly produced oils with fewer products of oxidation than their unprocessed counterparts, as measured by peroxide value (PV), thiobarbituric acid reactive substances (TBARS), and fatty acids (FA). Higher temperatures and longer smoking times resulted in correspondingly lower quantities of oxidative products in the oils. Fatty acid methyl ester (FAME) analysis of smoke-processed oils confirmed that polyunsaturated fatty acids (PUFA) were not being destroyed. Smoke-processing also imparted antioxidant potential to the extracted oils. Even when antioxidants, such as ethoxyquin or butylated hydroxytoluene, were added to raw oils, the smoke-processed oils still maintained lower levels of oxidation after 14 d of storage. However, decreased antioxidant capacity of smoke-processed oils was noted when they were heated above 75 degrees C. Vitamin studies supported the antioxidant results, with smoke-processed oils displaying higher levels of alpha-tocopherol than raw oils. Results suggest that smoking salmon prior to oil extraction can protect valuable PUFA-rich oils from oxidation. Improved preservation methods for marine oils may extend their usefulness when added as a supplement to enhance levels of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in foods.