Organic and conventional fertilization procedures on nitrate, antioxidants and pesticide content in parts of vegetables

Different parts of plant foods are generally discarded by consumers such as peel, stalk and leaves, which could although possess a nutritional value. However, few studies have analyzed the composition of these marginal foods. Phenolic compound, flavonoid, polyamine, nitrate and pesticide contents of parts of vegetables that are usually discarded, cultivated according to conventional and non-conventional procedures, were analyzed aiming to provide suggestions on how to improve the consumption of these parts and to reduce the production of urban solid wastes. Few, but significant, differences between the two manuring procedures were observed. Higher nitrate content and the presence of organochlorine pesticides were found in conventional cultivated papaya peel, lemon balm leaves, jack fruit pulp, beet stalk and peel. Discarded parts of plant foods such as stalk, leaves, and peels, can be used as a source of antioxidant compounds, such as phenolic compounds.