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Determination of nitrate contents of lettuce, tomatoes and potatoes on sale in Tehran central fruit and vegetable market by HPLC
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M Pourmoghim   , KH Khoshtinat * , A Sadeghi makkei , R Komeili fonod , B Golestan , M Pirali |
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Abstract: (21871 Views) |
| Background and Objectives: More than 80% of human dietary intake of nitrate comes from vegetables. Nitrate is converted to nitrite and nitrosacids, which can combine with primary and secondary amines, producing nitrosamines. Nitrosamines have hazardous effects on human health. Based on the results of the last National Food Consumption Survey in Iran (2002), lettuce, tomatoes and potatoes are the most widely consumed green leafy, fruit-bearing and tuberous vegetables. This study was carried out to determine the nitrate contents of these 3 vegetables on sale in the Tehran Central Fruit and Vegetable Market.
Materials and Methods: Three-Kg samples of lettuce, tomatoes, and potatoes, distributed in Tehran (Tehran Central Market, the Main Fruit, Vegetable and Agricultural Products Market) were taken during summer and winter 2007, at least 25 samples of each vegetable (a total of 157 samples). After separating inedible portions, the samples were washed, rinsed, minced, mixed thoroughly, freeze-dried and stored at -18◦C until analyzed. Nitrate was determined in the samples using HPLC based on the EC 12014-2 method, and Mann-Whitney nonparametric test, Kruskal-Wallis ANOVA and Bon-Ferroni multiple comparison were used for statistical analysis of the data.
Results: The mean concentration of nitrate in lettuce, tomatoes, and potatoes was 1123.46, 155.65, and 188.41 ppm, respectively. It is seen that the nitrate content of leafy vegetables was the highest, followed by fruit-bearing and tuberous vegetables. Nitrate accumulation in summer lettuce
(1223.57 ppm) was higher than in the winter sample (1046.82 ppm), but in the case of tomatoes and potatoes it was the other way round: 210.25 and 264.64 ppm in winter and 101.11 and 104.45 ppm in summer, respectively. The average nitrate contents of lettuce in both seasons were within the internationally permitted range, while in the case of winter potatoes and tomatoes the averages exceeded the respective permitted ranges.
Conclusion: Nitrate accumulation in vegetables can vary according to the harvesting season. Further research is recommended to determine the effects of such factors as variety, age, agricultural practices and storage conditions.
Keywords: Lettuce, Tomatoes, Potatoes, Nitrate, Nitrite |
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| Keywords: Lettuce, Tomatoes, Potatoes, Nitrate, Nitrite |
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Full-Text [PDF 756 kb]
(10218 Downloads)
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Article type: Research |
Subject:
Food Science
Received: 2010/03/9 | Published: 2010/04/15
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Pourmoghim M, Khoshtinat K, Sadeghi makkei A, Komeili fonod R, Golestan B, Pirali M. Determination of nitrate contents of lettuce, tomatoes and potatoes on sale in Tehran central fruit and vegetable market by HPLC. Iranian J Nutr Sci Food Technol 2010; 5 (1) :63-70 URL: http://nsft.sbmu.ac.ir/article-1-280-en.html
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