Nutritional composition, phenolic compounds, nitrate content in eatable vegetables obtained by conventional and certified organic grown culture subject to thermal treatment

The aim of this work was to analyse some nutritional characteristics in eatable vegetables obtained by conventional and organic grown culture, focusing on vegetable parts that are generally rejected by consumers. Samples of Chinese cabbage (Brassica rapa (syn. B. campestris) spp. pekinensis)) and maize (Zea mays L.) had been analysed under raw conditions and after thermal treatment in order to test modifications in protein, lipids, carbohydrate, phenol, nitrate content and dry weight. According to our results, thermal treatment modified some characteristics. Even if for most parameters significant differences between foods obtained by the two cultivation procedures had not been observed, in organic samples a higher concentration of nitrate was found. Furthermore, domestic processing, such as cooking in boiling water, seems to have a dramatic effect on phenolic content on both kinds of food, and, as a consequence, on antioxidant activity.