The role of peroxidase on the antioxidant potential of fresh-cut ‘Piel de Sapo’ melon packaged under different modified atmospheres

The effects of different initial in-package O2 and CO2 concentrations (2.5 kPa O2 + 7 kPa CO2, 10 kPa O2 + 7 kPa CO2, 21 kPa O2, 30 kPa O2 and 70 kPa O2) on peroxidase activity, vitamin C content, total phenolics and antioxidant capacity of fresh-cut ‘Piel de Sapo’ melon have been investigated for 14 days at 4 °C. The radical scavenging activity of fresh-cut melon strongly increased after 9 days storage related to a synthesis of phenolic compounds, especially under 2.5 kPa O2 + 7 kPa CO2 atmospheres. Low O2 levels best maintained vitamin C and phenolic content during the storage. However, stressful too-low O2 and high CO2 levels induced an important increase of peroxidase activity under 2.5 kPa O2 + 7 kPa CO2 atmosphere, which was directly related to changes of vitamin C throughout storage. Therefore, 70 kPa O2 atmospheres are proposed to prevent anaerobic conditions during storage of fresh-cut melon and thus, reduce wounding stress and deteriorative changes related to high peroxidase activity in tissue.