Pepper fruit as a model to study the metabolism of antioxidants, ROS and RNS.

Pepper (Capsicum annuum L.) is the second worldwide most consumed vegetable nowadays, with southern European countries being among the major producer areas. Pepper fruits contain high levels of vitamins A and C (ascorbate) and low calories what makes this produce greatly appropriate for human diet. In fact, fruits have enormous interest from the culinary and gastronomic points of view and can be used as raw, canned, condiment and food colorant, among others. Ripening of pepper fruits, an ethylene-independent process in this plant species, is somehow modulated by nitric oxide (NO), and the profile of several reactive nitrogen species (RNS) could be used as an index of this physiological stage. Regarding to the antioxidants' metabolism in fruits [1,2], it has been hypothesized that ascorbate plays an important role as a redox buffer during the ripening process. Furthermore, the interplay among enzymatic antioxidants protects pepper fruits against damage promoted by chilling conditions. The oxidative metabolism of peroxisomes seems to also participate in the regulation of the ripening process of fruits.