Comparision of Methods Used for Determination of Total Volatile Basic Nitrogen (TVB-N) in Rainbow Trout (Oncorhynchus mykiss)


Abstract: TVB-N (total volatile basic nitrogen) concentration in fish muscle was used as an index of freshness quality to compare the spoilage of rainbow trout wrapped in cling film and in aluminium foil. TVB-N levels in different muscle tissue and in the whole fish were measured every two days for a period of 16 days at 4-6°C. In addition, three different methods of determining of TVB-N were evaluated in terms of sensitivity, reliability, speed, and cost. Regardless of the method of analysis, there was an increase in the level of TVB-N during storage, especially after 7-9 days. In general, the trend of increase was similar in each method, but semi-steam distillation yielded the highest concentration of TVB-N. Results obtained also showed that TVB-N in the belly flesh sample was the highest, whereas the lowest TVB-N value was obtained with the dorsal flesh for each method. If the high cost can be tolerated, flow injection method is recommended for determination of TVB-N. It was also found, however, that TVB-N can not be used as an index of spoilage but as an indicator of advanced spoilage in the sample.

Keywords: TVB-N, rainbow trout, Conway micro-diffusion method, semi micro steam distillation, flow injection gas diffusion

Full Text: PDF