Storage disorder and ripening behavior of ‘Doyenne du Comice’ pears in relation to storage conditions

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‘Doyenne du Comice’ pears (Pyrus communis, L.) harvested at commercial maturity with flesh firmness (FF) of 55.1 N (±2.78 N) were stored in air and different controlled atmosphere (CA) conditions at −1 °C to evaluate storage disorder, ripening behavior and dessert quality after different storage intervals. Fruit stored in air developed both flesh breakdown (FB) and senescent scald (SCALD) disorders alter 4 months of storage. Incidence of FB and SCALD increased after 5 and 6 months of storage. Development of FB disorder in air-stored fruit was not associated with the activity of pyruvate decarboxylase (PDC) or alcohol dehydrogenase. Changes in α-farnesene and conjugated trienes in the peel tissue were highly associated with the development of SCALD. CA-stored fruit were free from SCALD disorder regardless of CA regime and storage time but developed internal browning (IB) disorder after 4 months of storage. Incidence of IB increased after 5 and 6 months of CA storage. Fruit stored in 0.5 and 1% O2 suffered higher incidence of IB than those stored in 1.5 and 2.0% O2. Symptoms of CA-induced IB are different from those of FB disorder, which resulted from prolonged air storage. The development of IB disorder was closely associated with an increase in PDC activity. Changes in ethylene production and FF during post-storage ripening at 20 °C were found to be the best objective measurements of storage life of ‘Doyenne du Comice’ fruit. Fruit stored in refrigerated air for 1–3 months exhibited typical climacteric-like patterns of ethylene production during 15 days at 20 °C and softened to proper ripeness with desirable eating quality on day 5 at 20 °C. The magnitude of ethylene production increased with storage time when initially transferred to temperature at 20 °C. Fruit stored in air for 4 months or longer did not exhibit climacteric-like patterns of ethylene production during ripening and softened improperly with coarse and dry texture. Fruit stored in either 1% O2/<0.1% CO2 or 2% O2/1% CO2 for 3 months (short-term CA storage) followed by holding in air at −1 °C for 1, 2, and 3 months were capable of ripening normally with desirable dessert quality without developing any physiological disorders. Short-term CA storage 4 of ‘Comice’ fruits maintained green skin color during 3 months of holding in air at −1 °C.