Numerous biochemical processes are involved in fruit maturation, such as ethylene production, phenolic compounds accumulation, and antioxidant enzymes production. Therefore, the aim of the present work was the evaluation of ethylene production, and the bioactive compounds change in the exocarp and mesocarp of five peach [Prunus persica (L.)] cultivars during three ripening stages, (1) early ripening (ER), (2) commercial maturation, and (3) full ripening (FR) in order to establish the best stage to harvest each peach variety. The experiment was applied to five peach cultivars growing within an arid bioclimatic environment covering the whole peach production season: two early cultivars, Flordastar and Early Maycrest; one variety of mid-season Rubirich; and two late cultivars, Sweet Cap and O'Henry. Ethylene production, phenolic compounds, and oxidative stress through antioxidant enzyme activities (catalase, peroxidases [PODs] Class III, and ascorbate-POD), malondialdehyde (MDA), and hydrogen peroxide (H2 O2 ) production were determined in the exocarp and mesocarp of peach fruits. The results showed a significant increase in ethylene production during fruit ripening. However, a parallel decrease in the level of phenolic compounds as well as in antioxidant enzyme activities was observed. The FR stage was also characterized by an important accumulation of MDA and H2 O2 . In conclusion, important changes in fruit quality associated with the production level of ethylene were observed. Fruits harvested during the ER stage would be more suitable for delivering to distant markets and more appreciated by the peach industries due to their highest phenolic acid content, best antioxidant enzyme activities, and lowest oxidative stress indicator.
Keywords: Prunus persica L; antioxidants; ethylene; exocarp; fruit quality; mesocarp.
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