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Concentrations of ammonia, monomethylamine (MMA), dimethylamine (DMA), trimethylamine (TMA), and trimethylamine oxide (TMAO) in raw and processed fish by-products were determined in coldwater marine fish using a capillary electrophoresis (CE) method. The CE method provides a fast and sensitive procedure to simultaneously quantify volatile amines and TMAO in raw and processed fish samples. Total volatile bases nitrogen (TVB-N) values were calculated from the concentrations of the respective individual volatile amines detected within the samples. TVB-N calculated concentrations ranged from a low of 12 ± 3.7 mg N/100g (n = 3) to a high value of 119.1 ± 27.2 mg N/100g (n = 3) wet weight for the raw fish by-products and from 60 ± 2.4 mg N/100g (n = 3) to 300.9 ± 40.5 mg N/100g (n = 3) dry weight for the processed fish byproducts. No MMA was detected in any of the samples tested. Raw viscera samples contained increased concentrations of DMA and TMA relative to the other samples tested. High levels of TMAO and TMA in the freezedried stickwater suggested decomposition of TMAO and/or fractionation into the stickwater during processing since these compounds are water soluble. Results indicated that there is a wide distribution on the levels of TMAO, ammonia, TMA, DMA, and calculated TVB-N in the materials

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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.