LAUSR

In situ recording of the voltammetric profile of different apple (Malus domestica Borkh.) varieties (Golden, Granny Smith, Reineta, Red delicious, Fuji, and Braeburn) without and with ROS generation is reported. The voltammetric response associated to the oxidation of ascorbic acid (AA) and polyphenolic (PPs) components was recorded. The obtained voltammetric profiles were satisfactorily fitted to a theoretical kinetic model consisting of the competing, dual activation pathways of AA and PPs followed by a degradative step. The rate constants for these processes were calculated from voltammetric data revealing significant differences between varieties. The activation pathways as well as the influence of electrochemical ROS generation on it were variety-sensitive while the degradative step was almost variety insensitive and lightly sensitive to ROS generation.