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Title: Ammonia, Dimethylamine, Trimethylamine, and Trimethylamine Oxide from Raw and Processed Fish By-Products

Author
item Wu, Ted
item Bechtel, Peter

Submitted to: Journal of Aquatic Food Product Technology
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 2/20/2008
Publication Date: 3/20/2008
Citation: Wu, T.H., Bechtel, P.J. 2008. Ammonia, Dimethylamine, Trimethylamine, and Trimethylamine Oxide from Raw and Processed Fish By-Products. Journal of Aquatic Food Product Technology. 17(1):27-38. doi: 10.1080/10498850801891140.

Interpretive Summary: Different fish parts from various cold water marine fish were examined for compounds that are related to the freshness in seafood using capillary electrophoresis (CE). In addition processed fish parts were also examined. CE is a fast, sensitive, and powerful technique for the identification of these individual compounds that relate to the freshness of seafood . The results from the raw and processed fish parts suggested there are a wide distribution of volatile amine compounds, which indicate a potential to obtain different levels of freshness by segregating raw fish parts and the potential to alter levels of volatile amine compounds related to freshness during processing.

Technical Abstract: Concentrations of ammonia, monomethylamine (MMA), dimethylamine (DMA), trimethylamine (TMA) and trimethylamine oxide (TMAO) in raw and processed fish by-products were determined in cold water 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 14.6 ± 4.5 mg/100g (n=3) to a high value of 259 ± 86.1 mg/100g (n=3) wet weight for the raw fish by-products and from 106 ± 73.2 mg/100g (n=3) to 871 ± 101 mg/100g (n=3) dry weight for the processed fish by-products. 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 freeze dry stickwater suggested decomposition of TMAO and/or fractionation into the stickwater during processing since these compounds are water soluble. Results indicated there is a wide distribution on the levels of TMAO, ammonia, TMA and DMA and calculated TVB-N in the materials tested. It is possible these values can be used as quality indicators of raw material freshness and as indicators for the potential to spoil. Values for processed fish by-product tested can also be use as quality indicators.