Acording to M.Carbonaro, M.Mattera et al despite the increasing interest in organic products, knowledge about how different levels of fertilization affect nutritionally relevant components is still limited. The concentration of polyphenols and the activity of polyphenoloxidase (PPO), together with the content in ascorbic acid, citric acid, and α- and γ-tocopherol, were assayed in conventional and organic peach (Prunus persica L., cv. Regina bianca). 2-Thiobarbituric acid reactive substances and the tocopherolquinone/α-tocopherol ratio were used as markers of oxidative damage in fruits. A parallel increase in polyphenol content and PPO activity of organic peach as compared with the corresponding conventional samples was found. Ascorbic and citric acids was higher in organic than conventional peach. These data provide evidence that an improvement in the antioxidant defense system of the plant occurred as a consequence of the organic cultivation practice. The concentration of oxidation products in the organic sample was comparable to that of the corresponding conventional sample. This is likely to exert protection against damage of fruit when grown in the absence of pesticides.
I have been looking for information about the chemical composition of conventional and organic peaches and I have not found enough information about the chemical composition.