Determination of Nitrate Concentration of Consumed Vegetables and Fruits in Ardabil

Excessive amounts of nitrate and nitrite in food causes to increasing the risk of gut and intestinal cancer in adults and met-hemoglobinemia disease in infants. Human body intake about 80% of nitrate from fruits and vegetables. This research carried out with the aim of determining the nitrate concentration of fruits and vegetables consumed by Ardabil citizens and to compare with acceptable levels. Samples of fruits and vegetables were collected from 10 markets around Ardabil city in September and October of 2009. The samples were washed two times with tap and distilled water, dried at 55 ºC and their moisture content were measured. Samples were ground with regular and ball mills and 0.025 molar aluminum sulfate solution was used to extraction. Nitrate concentration of extracts was measured with anion selective apparatus with nitrate electrode. To investigate the possibility of nitrate intake reduction by peeling, the skin and meat of some fruits and vegetables samples were measured, separately. SPSS software was used for determining of mean and standard deviation of sample's nitrate concentration. Duncan multiple range test was used for grouping of fruits and vegetables in the respect of their nitrate concentration. The concentration of nitrate in leafy vegetables was higher than those of root and glandy vegetables. Fruits had lower nitrate concentration than vegetables. The highest nitrate concentrations were observed in spring onion, purple headed cabbage, and spinach with the amounts of 1555.8, 1394.8, and 1021 mg/kg of wet weight and lowest belonged to red and golden apples with the amounts of 29.7 and 29.9 mg/kg, respectively. Most of fruits and vegetables samples had lower nitrate than acceptable levels. With regards to high consumption rate of some fruits and vegetables and great variation of nitrate concentration, additional investigation and permanent control of their nitrate concentration is necessary.