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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: Stabilizing Oils from Smoked Pink Salmon (Oncorhynchus gorbuscha)

Authors
item Bower, Cynthia
item Hietala, Katie
item Oliveira, A.C.M. - UNIV. OF ALASKA FITC
item Wu, Ted

Submitted to: Journal of Food Science
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: January 5, 2009
Publication Date: April 20, 2009
Citation: Bower, C.K., Hietala, K.A., Oliveira, A., Wu, T.H. 2009. Stabilizing Oils from Smoked Pink Salmon (Oncorhynchus gorbuscha). Journal of Food Science. 74(3):C248-C257.

Interpretive Summary: 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 °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 Nonesterified fatty acids (NEFA). 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 PUFAs were not being destroyed. Smoke processing also imparted antioxidant potential to salmon oils, as compared to raw oils, which possessed none. 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 days. However, decreased antioxidant capacity of smoke-processed oils was noted when they were heated above 75 °C. Vitamin studies supported the antioxidant results, with smoke-processed oils displaying higher levels of alpha-tocopherol than raw oils. This research suggests that smoking salmon prior to oil extraction can protect valuable PUFA-rich oils from oxidation. Improved preservation methods for marine oils may extend their shelf life when added as a supplement to enhance levels of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in foods.

Technical 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 °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 Nonesterified fatty acids (NEFA). 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 PUFAs were not being destroyed. Smoke processing also imparted antioxidant potential to salmon oils, as compared to raw oils, which possessed none. 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 days. However, decreased antioxidant capacity of smoke-processed oils was noted when they were heated above 75 °C. Vitamin studies supported the antioxidant results, with smoke-processed oils displaying higher levels of alpha-tocopherol than raw oils. This research suggests that smoking salmon prior to oil extraction can protect valuable PUFA-rich oils from oxidation. Improved preservation methods for marine oils may extend their shelf life when added as a supplement to enhance levels of eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA) in foods.

Last Modified: 7/23/2014
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