Effect of Methodology on the Determination of Total Volatile Basic Nitrogen as an Index of Quality of Meat and Fish

Determination of TVB-N values expressed as mg /100g of fresh meat and fish using four different methods (Conway’s Microdiffusion; Direct water vapor distillation with MgO; water vapour distillation of an acidic extract using Perchloric acid 6% and vapour distillation of an acidic extract using trichloroacetic acid 7.5%) were evaluated during storage in refrigerator till the beginning of spoilage. The results revealed that there was an increase in the level of TVB-N during storage of fresh meat from 4.03±0.152, 6.72±0.37, 6.18±4.59 and 6.62±0.7 at 1st day to 43±0.31, 50.08±0.5, 47.1±0.32 and 47.8±0.33 at 11th day, respectively and the mean values of TVB-N mg/100g of fresh fish were 5.03±1.12, 7.71±0.58, 7.14±0.47 and 6.42±0.43 to 66.5±0.39, 73±0.1, 70.67±1.48 and 70.2±1.04 respectively. Direct water vapor distillation with MgO yielded the highest concentration of TVB-N, whereas the lowest TVB-N value was obtained with the Conway’s Microdiffusion method. The accuracy % of detection of nitrogen in mg/100g from 100ml standard solution contained 210.9 mg nitrogen using the four methods were 64.84, 69.43, 99.81 and 100.73 respectively.