Trimethylamine Nitrogen Research Articles

Bacteriological and Shelf-Life Characteristics of Canned, Pasteurized Crab Cake Mix

The bacteriological spoilage characteristics of a canned, pasteurized crab cake mix product stored at various temperatures were investigated. A large number of bacteria, both mesophilic and psychrophilic, survived the pasteurization process. Bacillus and Micrococcus were found to predominate when the product was stored at 30 C (86 F) and 18 C (64 F), whereas Alcaligenes predominated at 2 C (36 F). The product was found to be free of Escherichia coli. Bacterial counts, trimethylamine nitrogen, volatile reducing substances, and ammonia determinations were evaluated as indices of quality for the product. Close correlation was observed between bacterial counts, volatile reducing substance values, and organoleptic tests when the product was stored at 30 C (86 F). The shelf-life of the product was approximately 6 months at 2 C (36 F), 4 days at 18 C (64 F), and 27 hr at 30 C (86 F).

Use of EDTA Compounds for the Preservation of Haddock Fillets

Studies of the effect of treatment of haddock (Melanogrammus aeglefinus) with solutions of sodium salts of ethylenediaminetetraacetic acid (EDTA) have shown that a 1% solution of tetrasodium EDTA used as a dip can extend the storage life in ice (0 C) for 11 days over that of untreated controls. The texture of these fillets remained acceptable for the whole of their storage lives.Fillets treated with 0.5 and 0.75% tetrasodium EDTA had a storage life extension of 5 days and those treated with 1% disodium EDTA had a storage life of 6 days longer than the untreated control fillets. Fillets treated with 0.5 and 1.0% disodium calcium EDTA solution showed 0- and 1-day storage life extension respectively.Increase in trimethylamine (TMA) during storage was reduced by treatment with EDTA with the tetrasodium EDTA-treated fillets having the lowest rate of increase. Samples were rejected by the taste panel as spoiled with TMA values of between 3 and 9.5 mg TMA nitrogen (TMA-N) per 100 g.Although treatment of fillets with EDTA extended the storage life in ice and suppressed the increase in TMA, there was little or no effect on the growth of the bacterial population.

Determination of Trimethylamine Nitrogen in Extracts and in Volatile Fractions of Fish

Abstract Dyer’s colorimetric procedure was applied to the determination of trimethylamine nitrogen (TMA-N) in distillates from frozen cod and frozen haddock. Studies show that a more accurate estimate of the TMA-N contained in fish is obtained when this colorimetric method is applied to the distillates rather than to the extract. The method is also shortened by the elimination of one distillation, two oxidations, and two titrations.

Effect of Tetracycline Antibiotics on Objective and Subjective Fish Quality Tests

The effect of the antibiotics chlortetracycline and oxytetracycline on certain fish quality tests (viable bacterial count, trimethylamine nitrogen content and organoleptic rating) was evaluated. The formation of trimethylamine by the reduction of trimethylamine oxide in lingcod muscle was suppressed when chlortetracycline and oxytetracycline were used as preservatives in storage tests at 0 and 4 °C. Results of the three tests on antibiotic-treated samples showed poor agreement; reasonable agreement was obtained from the tests on control samples.

鯨肉の鮮度に關する化學的研究 第1報

In the lowering of freshness of tail meat of a whale (Balaenoptera) at room temperature, it was found that the amount of volatile basic nitrogen and Formol titrated nigrogen both increase regularly with passage of time and the rate of increase was great. The increse of non-protein nitrogen and trimethyl amine nitrogen was comparatively small and no change was observed in the amount of trimethyl amine-oxide nitrogen. At the beginning of putrefaction amount of volatile basic N per 100g sample was 30.2mg, nonprotein N 500mg; Formol titrated N 136mg; and trimethyl amine N 0.45mg. A comparison of percentage freshness and the amounts of volatile basic N and Formol titrated N at the time of the dissection of a sperm whale, showed that both N gradually but distincly increase with the lowering of freshness between 90%-70% freshness but below 70%, the amount of volatile basic N increases rapidly. As a result of these experiments it has been shown that the freshness of a whale meat could be evaluated by the determination of volatile basic N or Formol titrated N.

Amines in Fish Muscle: I. Colorimetric Determination of Trimethylamine as the Picrate Salt

A sensitive accurate colorimetric method for trimethylamine determination is presented, based on the extraction with toluene of an alkaline sample containing 0.002 to 0.02 mg. trimethylamine nitrogen, and the formation of the yellow coloured picrate by mixing with a picric acid reagent. The application of the method in fishery products and effects of interfering substances have been investigated.