[Evaluation of nitrate, nitrite and total protein content in selected vegetables cultivated conventionally and...

Nitrates, nitrites and total protein content in selected vegetables from conventional and ecological farms were estimated. The beetroots, carrots, potatoes available on market or special shops in January, May and March were evaluated. The content of nitrates and nitrites was determined by colorimetric method with Griess reagent after previous reduction of nitrates to nitrites by metallic cadmium. Total protein content was determined by Kjel-Foss Automatic 16210 analyser working on the basis of classical Kjeldahl method. The higher content of nitrates was found in vegetables from conventional farms. Amounts of nitrates in both groups of vegetables did not exceed allowed limits. Levels of nitrites in ecological and conventional vegetables were similar-above 0.5 mg NaNO2/kg (except conventional potatoes from January). Slightly more content of protein was recorded in conventional vegetables.