Spectrophotometric determination of trimethylamine-nitrogen in cadaver tissues for the estimation of late postmortem interval: a pilot study / 华中科技大学学报（医学）（英德文版）

To study the relationship between the late postmortem interval (PMI) and trimethylamine-nitrogen (TMA-N) in postmortem tissues of cadaver, TMA-N in muscles, livers and kidneys of rats was measured at different postmortem intervals (PMI) by using a modified spectrophotometric method. The results indicated that the detection sensitivity of TMA-N was 1 mg/L, and there was a good linear correlation between the value of absorbance (A value) and TMA-N at the concentration of 1-10 mg/L (R (2) = 0.9991). Although TMA variation in muscles was different from that in inner organs during the time since death, TMA-N changes in cadaver tissues was positively correlated with PMI. During 2 to 7 d since death, the best correlation between PMI and TMA-N concentration was found in muscles. With PMI as an independent variable, the cubic polynomial regression equation was y= -0.457x(3)+6.519x(2)-24.574x+27.207 (R (2)=0.969). During 3 to 8 days since death, PMI was best correlated with TMA-N concentration in inner organs. With PMI as the independent variable, the cubic polynomial regression equation was y=0.509x(3)-9.153x(2)+55.727x-95.819 (R (2)=0.953). It was concluded that TMA-N in tissues could be used as a new estimator for late PMI. The method used in this study offered advantages such as accuracy, sensitivity, little samples required and wide PMI estimation.

Efecto de tratamientos térmicos sobre las características químicas de carne de jaiba mora (Homalaspis plana) / Effect of thermal treatments on the chemical characteristics of mora crab meat (Homalaspis plana)

Marine species muscles present non-proteins nitrogenated compounds, used as quality index. They are total volatile basis (NBVT), trimethylamine oxide (TMAO) and trimethylamine (TMA). pH is considered too as a quality index. The aim of this work was to evaluate these parameters in a fresh and canned marine product from the V region, corresponding to mora crab (Homalaspis plana). Fresh pincer meat from mora crab was extracted and kept in ice until theits analysis and thermal process of the canned product. A 3(2) statistical design was applied, considering two variables with 3 levels: 15, 30 y 45 minutes time levels: 80 degrees, 100 degrees y 121 degrees C temperature levels. Nine conditions of time-temperature were obtained. The thermal treatment caused an increase in pH and BVT. The TMA was increased since reduction of TMAO.

Estudio de los niveles de los precursores de los compuestos N-nitroso cancerígenos en algunas especies de peces cubanos: I. Nitratos, nitritos y trimetilamina en ronco (Haemulon parra Desmarest) / Levels of precursors of N-nitrous carcinogenic compounds in some species of Cuban fishes: I. nitrates, nitrites and trimethylamine in ronco (Haemulon parra Desmarest)

Entre los precursores de la síntesis de la dimetilnitrosamina cancerígena se encuentran los nitratos, nitritos y la trimetilamina (TMA). En el presente trabajo se informan los niveles de estos precursores en 30 muestras de pescado de la especie Haemulon parra Desmarest (ronco), capturadas en la plataforma cubana. Los métodos de análisis empleados fueron: para nitratos y nitritos el recomendado por el Comité Mixto FAO/OMS en 1976 y para la trimetilamina el informado por la FAO en 1969. Los resultados obtenidos (x+ ou - S) expresados en mg/kg fueron: TMA 9,7 + ou - 6,63; NaNO3 11,7 + ou - 8,34 y NaNO2 1,0. Los niveles hallados no parecen representar un riesgo a la salud por la ingestión de estos compuestos, en comparación con otros alimentos, incluyendo otras especies de peces informados en la literatura. La posibilidad de formación de dimetilnitrosamina en las muestras analizadas a partir de los precursores estudiados es muy escasa, dados los bajos contenidos encontrados de TMA, NaNO3 y sobre todo NaNO2