Fish is one of the most easily perishable food because of its peculiar chemical composition; therefore, it‘s important to evaluate its freshness, both for commercial aspects, and from food safety and hygiene point of view. The protein degradative processes, occurring during fish perishing, produce an increase of typical substances, such as ammonia and volatile nitrogen compounds, and the concentrations of which are index of the deterioration status.
The TVBN (Total Volatile Basic Nitrogen) is a method of analysis that quantifies the presence of nitrogenous compounds (ammonia and dimethyl and trimethyl amine) in fish from the sea or from river, revealing the degree of freshness.
TVBN Determination in fresh and frozen fish
One of the routine methods which may be used to check the TVBN is the “microdiffusion method” described by Conway and Byrne (1933).
The sample is alkalized by magnesium oxide (MgO). Then the TVBN is determined by steam distillation and titration: the Automatic Distillation and Titration System UDK 159 is suitable for this kind of application.
Download the full application note here.