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Internal browning disorders in 'Rocha' pear stored under high CO2 atmospheres are triggered by oxidative stress

Duchande, T., Fidalgo, F., Vasconcelos, M., Costa, D. V. T. A., Larrigaudiere, C.
Acta horticulturae 2015 no.1071 pp. 771-778
Pyrus communis, antioxidants, carbon dioxide, controlled atmosphere storage, dehydroascorbic acid, enzyme activity, fruits, metabolism, oxidative stress, oxygen, pears, plant damage, storage time, superoxide dismutase
The aim of this work was to study the physiological basis, with special emphasis on antioxidant metabolism, of CO2-related internal browning disorders in ‘Rocha’ pear (Pyrus communis L. ‘Rocha’) during storage under different controlled atmosphere (CA) conditions. Pears were stored for 5 months at 0°C and 3% O2 + 0.5% CO2 (normal CA storage) or up to 4 months at 0°C and 1% O2 + 10% CO2 (browning inducing CA storage) and the internal browning disorders were evaluated after 30, 60 and 120 days of storage. Changes in antioxidant enzyme activities (SOD, CAT, APX and POX), ascorbic (AsA) and dehydroascorbic acid (DHA) were also evaluated after 7, 15, 30 and 60 days of storage aiming at assessing the relationship between oxidative stress and internal disorders. During the entire storage period under normal CA up to 5 months, fruits did not develop browning disorders. In contrast, fruit stored under high CO2 atmospheres exhibited high levels of internal browning (70% of damaged fruit) after 4 months of storage. High disorder incidence at high CO2 levels was related to a decrease of total ascorbate levels during storage. Internal disorder incidence was also related to greater SOD, and to some extent APX activities as well as higher DHA/AsA ratios. Collectively these results suggest that internal disorders in ‘Rocha’ pear under high CO2 atmosphere are the consequence of an oxidative stress within the fruit.