Phytochemical screenings, physicochemical properties and effects of pesticides on vegetables
Shoeb M, Sharmin Sultana, Nasrin Jahan, Nilufar Nahar and Waziha Farha

Vegetables contain minerals, vitamins, and other beneficiary constituents for a balanced diet. The nutritional value of vegetables may be affected by the application of pesticides which are indiscriminately used in Bangladesh to increase crop production. To study the effects of pesticides on the nutritional values of vegetables, bitter gourd (Momordica charantia L.), tomato (Solanum lycopersicum L.), chili (Capsicum annum L.), eggplant (Solanum melongena), pumpkin (Cucurbita pepo) and bottle gourd (Lagearia sicreraria) were collected from vegetable growing field of Nurundi, Jamalpur, Bangladesh. Two insecticides, cypermethrin, and emamectin benzoate, and one fungicide mancozeb were sprayed in the vegetable field. The water content of pesticides treated and untreated samples were very similar within the range of 85-94%, whereas ash content of treated samples decreased in the case of cypermethrin and emamectin benzoate but increased in the case of mancozeb. The vegetable samples were screened for minor and major phytochemicals. Phytochemical screening revealed the presence of tannins, glycosides, saponins, proteins, and carbohydrates in untreated and pesticide-treated vegetables except for glycosides which were missing in treated vegetables. Percent carbohydrates in the pesticide-treated and untreated samples were not significantly changed. The level of Ca, Cu, Fe, Zn, Mg, Mn and K were in the range of 0.95-4.1, 0.009-0.79, 0.05- 1.14, 0.01-0.13, 0.10-3.40, 0.003-0.15 and 15.67-26.49 mg/g, respectively. The results obtained are an affirmation of the use of these vegetables (treated with pesticides) and thus these vegetables may serve as sources of safe food for consumption.

Keywords: Ash content, pesticides, phytochemical screening, vegetables, water content