Abstract:

Nitrite can accelerate the oxidation reaction of methyl blue with potassium bromate in acidic medium, which causes the color fading of methyl blue. Based on it, a detection method for the trace nitrite in food was developed in the present study. The maximum absorption peak of the reaction system was presented at 550 nm, and in the nitrite concentration of 0.2－1.2 μg/ml there was a good linear correlation (r = 0.994). The average spike recovery in meat products was 93.16%. The nitrite contents in Chinese sausage, red sausage, nitrite pork, nitrite beef and nitrite pork chop were (15.27 ± 0.08), (4.15±0.13), (90.57 ± 1.69), (99.83 ± 2.75) and (52.13 ± 1.10) mg/kg, respectively. The nitrite content in Chinese cabbage increased with the prolongation of storage time, and reached 6.97 mg/kg when the decay of Chinese cabbage happened.

Key words: nitrite, methyl blue, potassium bromate, determination