Quality and nutritional value of vegetables from organic and conventional farming

• The quality of organically grown cauliflower, endive and zucchini was investigated.
• Organic farming per se does not necessarily improve vegetables nutritional quality.
• Many variables (cultivar, fertilization, soil type) interact in determining quality.
• Controlling some growth determinants enhances the accumulation of useful molecules.

Consumers demand for healthier food and governments’ policies for environmental sustainability of agricultural processes are increasingly promoting a rapid expansion of organic farming. Nevertheless, the link between organic products and their enhanced nutritional/environmental values is far from being fully understood. In this context, we have begun to assess the effect of cultivation variables that may interact with farming systems and ultimately affect the final product quality. By comparing the response to conventional vs. organic farming of cauliflower, endive and zucchini here we demonstrate that the overall quality of organic products depends on many interacting variables. In cauliflower, the cultivar effect overwhelms other quality determinants with respect to antioxidant activity and nitrate accumulation. In endive, the liposoluble antioxidant activity increases under organic cultivation only in the absence of mulching. Finally, organic farming promotes the accumulation of K in zucchini grown on clay but not on sandy soil. Therefore, understanding the functional links between cultivation variables and physiological responses is essential to improve and standardize the quality of organic products.