Effect of wilting and processing on the nitrate and nitrite contents of some Nigerian leaf vegetables

Nitrate and nitrite contents of seven varieties of commonly consumed leaf vegetables were determined. Effect of cooking and wilting on the contents of these factors were investigated. Nitrate ranged from 48.10 in ewuro to 270.0 ppm ogunmo (mean 116.43+/- 78.31) while nitrite ranged from 0.024 ppm in tete to 0.064 in ogunmo (mean 0.044+/-0.018). Cooking reduced the nitrate levels in all the samples but nitrite levels inexplicably increased in all sample. On wilting nitrate levels decrease while nitrite levels increased up to 83% in tete. The nitrate and nitrite levels were not considered hazardous but toxicological implications of high consumption of these factors is briefly highlighted.