Determination of Nitrate and Nitrite Contents of Some Edible Vegetables in Guyuk Local Government Area of Adamawa State, Nigeria

Abstract

Based on research founding’s nitrite and nitrate has been discovered as pro-drugs of the vasorelaxant nitric oxide, however many studies have reported that intake of these ions either intravenously or as a food supplements enhanced athletic performance. One of the factors and major causes of gastrointestinal cancer in adults and Methemoglobinemia (blue baby syndrome) in children is nitrosamine derived from nitrate. Approximately 80 to 90 percent of nitrate which enters the human body is through vegetables and fruits, in this present study nitrate and nitrite concentrations in fresh leafy and fruits vegetables in Guyuk was determined and compared with WHO standard limit. The levels of nitrate and nitrite were determined in six edible vegetable samples consumed and cultivated in Guyuk Local Government area of Adamawa State, Nigeria. The vegetables studied were Spinacea oleracea (spinach), Amaranthus caudatus (Amaranthus), Lycopersicum esculentum (Tomato), Allium cepa (onion), Abelmoschus esculent (Okra), and Brassica oleracea (Cabbage). The nitrate and nitrite concentrations were analyzed by ultraviolet spectrophotometer method. The results of the present investigation showed no any significant difference in nitrate levels found in most vegetables cultivated during the dry and rainy season harvests. Statistically, the mean nitrates level was higher in spinach (52.50±4.00 mg/kg to 53.50±4.50 mg/kg), Amaranthus (43.50±3.50 mg/kg to 47.50±2.50 mg/kg), Okra (39.00±2.10 mg/kg to 40.50±0.90 mg/kg) and onion (37.50±0.40 mg/kg to 39.00±1.60 mg/kg), intermediate in tomato (34.50±2.40 mg/kg to 36.50±2.40 mg/ kg), and lower in cabbage (15.00±1.60 mg/kg to 20.50±1.50 mg /kg), as compared with those in other vegetables. However, it was discovered that the level of nitrate in all the edible studied vegetable samples was lower than the WHO standard limit. The concentration of nitrite in the different studied vegetables exceeded 1.0 mg/ kg, but is within the permissible limit of the WHO Standard limit. It was observed that the values have no significant difference among most vegetables. It was also noted that nitrate contents in the studied vegetables differs, depending on the kinds of vegetables and were comparable and similar to those vegetables grown and cultivated in other countries.