Background and Objective: Much of the nitrate consumption by humans in the daily diet comes from VEGETABLES. The high concentration of nitrate in edible parts of VEGETABLES causes toxicity, anemia for children and nitrous amine production in adults. Nitrous amine may results in cancer. Samples were collected from four main vegetable markets in Kermanshah city in summer 2019 to investigate the concentrations of these compounds in edible VEGETABLES with high consumption. Materials and Methods: After preparation of the samples in a laboratory, the nitrate were extracted and its concentration was determined by a spectrophotometer at wavelength 410 nm. Results: The results showed significant differences in nitrate concentrations for the vegetable samples taken from the different markets (p>0. 05). The highest concentration of nitrate were observed in the leafy, tuberous, and fruit-bearing VEGETABLES. The highest nitrate concentration among the leafy VEGETABLES was observed in cress with an average of 2052. 14 mg/kg Fresh Weight; among tuberous VEGETABLES was potato with an average of 127. 01 mg/kg Fresh Weight; and among fruit-bearing VEGETABLES was cucumber with an average of 37. 20 mg/ kg Fresh Weight. Conclusion: The nitrate concentrations for celery, and red onion at the Azadi market were higher than the permissible limit, according to the national standard. Also, the nitrate concentrations in sugar beet leave and potato at the Toopkhaneh Market and nitrate concentration in cress at all the markets were higher than the permissible limit. It is recommended that the concentration of nitrate of edible VEGETABLES should be determined at regular time intervals as well as during different seasons.

In this research the drying of four kinds of VEGETABLES was investigated in a vacuum dryer.The effect of temperature on drying rate of samples at various temperatures (30, 35 and 45oC) was studied. Six thin-layer drying models were fitted to drying data and suitable model was selected from them. Then effective moisture diffusivity and activation energy of samples were calculated.The Diffusion approximation model gave excellent fit for fenugreek and mint leaves and vegetative parts of leek and the page model was considered adequate to describe the thin-layer drying behavior of parsley leaves. The effective diffusivity values changed from 2.92x10 -10 to 9.81x10 -10, 1.77x10 -10 to 5.99x10 -10, 9.3x10 -11 to 1.7x10 -10 and 1.27x10 -9 to 3.4x10 -9 for fenugreek, mint and parsley leaves and vegetative parts of leek, respectively. An Arrhenius type of equation was used to evaluate the effect of temperature on the effective diffusivity and the activation energy values was found 66.36, 66.34, 32.27 and 51.16 kJ/ mol for fenugreek, mint and parsley leaves and vegetative parts of leek, respectively.

Understanding agricultural biodiversity is the first step in determining the effects of intensive and monocropping systems and use of high yield cultivars on sustainability of agricultural systems. For this purpose biodiversity of fruits and VEGETABLES in Iran was studied. Results indicated that many fruits and VEGETABLES are cultivated in country, and therefore the number of cultivated species or species richness is considerable. Shannon index indicated that diversity of these crops is not proportional to species richness, which caused from unevenness distribution of cultivated land between crops, and possibly, high monoculture with regard to climatic conditions. Shannon index for fruits and VEGETABLES in different provinces was rather high. However, due to lack of data on number of varieties cultivated, biodiversity at variety level which is an important index was not calculated.

Introduction: Nitrogen is essential for plant growth. Excessive use of nitrogen fertilizers causes nitrate uptake and accumulation in edible parts of plants. This study was conducted to evaluate the nitrate concentration in some VEGETABLES collected from the Kermanshah vegetable market in winter 2020. Material and methods: vegetable samples include leafy, fruit-bearing, and tuberous VEGETABLES were collected from the main vegetable market in Kermanshah city four times. Leafy samples were cress, lettuce, spinach, and celery. Fruit-bearing samples included cucumber and tomato. Tuberous samples included red and yellow onions and potatoes. The sampling times were January, early and mid-February, and March. Our previous study showed that VEGETABLES in the main vegetable market of Kermanshah have been provided by different cities of Iran. Therefore, if there was one vegetable type has been supplied from different locations or different cultivation methods (i. e. traditionally vs. in greenhouse conditions), individual samples were collected. The nitrate concentration of vegetable samples was determined by the colorimetric method (Cataldo et al., 1975) after their preparation and extraction (Jones, 2001). The results were analyzed via SPSS v. 26 by one-way ANOVA after testing the normal distribution. The means were compared by Duncan’s test (P<0. 05). However, to determine the health status of VEGETABLES, their concentrations were compared with the nitrate limit defined by the World Health Organization (WHO) (WHO, 1978) and the Institute of Standards and Industrial Research of Iran (ISIRI) (ISIIR, 2013). The differences in nitrate concentration of crops were also compared according to the time of sampling, the place (i. e. city that crops were grown), and the cultivation methods. Results and discussion: The results showed that nitrate concentration in lettuce, celery, cucumber, tomato, yellow onion, and potato was significantly lower than the ISIRI nitrate limit (P<0. 001). Also, the nitrate concentration in cress samples in last February and March, spinach samples in mid-and las-February, and red onion samples in January and mid-February were lower than the permissible nitrate limit. However, nitrate concentration in cress and red onion (in January and mid-February) and spinach (in January and March) was higher than the WHO and ISIRI nitrate limit. ANOVA results revealed significant differences in vegetable nitrate concentration between months (P<0. 001). The results also indicated that the variances of nitrate concentration in cress, cucumber, and tomato samples were highly influenced by place (P<0. 01). Moreover, nitrate concentration in the above-mentioned samples traditionally cultivated was found to be not significantly different from those grown in the greenhouse. Conclusions: The results of this study showed that the time of sampling and the place where VEGETABLES are grown affects the variation of nitrate concentration. However, the cultivation method showed no significant impact. However, the number of samples in this study was less than the amount to conclude this result certainly. Therefore, it is recommended that the nitrate concentration of the VEGETABLES be measured at different sampling times as well as for VEGETABLES grown in different places with more samples to assess the status of nitrate more confidently. This would help to have a reasonable allowable nitrate concentration limit for VEGETABLES in comparison with the WHO standard.