Concentrations of total phenols and antioxidant activity in apple do not differ between conventional and organic orchard management

Abstract

The apple is one of the most widely consumed fresh fruits in the world. It constitutes a major contribution of phytochemical compounds to the diet, which are associated with a reduced risk to develop degenerative diseases. The main objective of this study was to evaluate the effects of conventional and organic management of apple cultivation, the stage of development and sunburn damage on polyphenol concentrations, antioxidant activity and pigments in three apple cultivars. Two experiments were carried out during the 2009/2010 season to study (1) the effect of the type of management and the development stage of the fruit during the season on the concentration and content of total and specific phenolics, antioxidant activity in the whole fruit, and pigments (chlorophylls, carotenoids and anthocyanins) in the peel of cvs. Gala (Galaxy and Brookfield), Granny Smith and Fuji (Raku Raku and Stripped) and (2) the effect of the type of management and the presence of sunburn at harvest on phenolics concentrations and antioxidant activity in both the whole fruit and peel, as well as pigments in peel, in two cultivars. Phenolics concentrations and antioxidant activity increased in the first weeks of fruit development and then decreased until harvest. The concentration of chlorophyll and carotenoids tended to decrease throughout the season, while anthocyanin concentration increased. In the case of tissue damaged by sunburn, phenolics concentrations and antioxidant activity were higher in damaged fruit, while changes in pigment concentrations varied according to the cultivar. The practices of conventional and organic management did neither influence significantly phenolics and pigments concentrations and antioxidant activity, except at certain stages of fruit development.