Residual effects of low oxygen storage of mature green fruit on ripening processes and ester biosynthesis during ripening in bananas

Mature green banana (Musa sapientum L cv. Cavendish) fruit were stored in 0.5%, 2%, or 21% O-2 for 7 days at 20 degrees C before ripening was initiated by ethylene. Residual effects of low O-2 storage in mature green fruit on ripening and ester biosynthesis in fruit were investigated during ripening for up to 6 d at 20 degrees C. Concentrations of ethanol in mature green fruit did not change during storage in both 21% and 2% O-2 atmospheres, but increased in fruit stored in 0.5% O-2. The activities of alcohol dehydrogenase (ADH) in 2% and 21%O-2 atmospheres remained very low throughout the storage period, but significantly increased with 0.5% O-2. After transferring fruit to regular air and trigging ripening with ethylene, yellowing of peel, fruit softening and hydrolysis of starch in fruit stored in low O-2 atmospheres were slower than in the control. Fruit stored in low O-2 also showed a delayed onset of the climacteric peak. The activities of ADH were lower in the low O-2 stored fruit than in the control fruit. Productions of ethyl acetate, isoamyl acetate, and isobutyl acetate were remarkably suppressed by low O-2 storage. Alcohol acetyltransferase activity increased gradually with storage time in all treatments, being significantly lower in fruit with low O-2 pretreatments. The results indicate that low O-2 plus room temperature storage can extend storage life of bananas with the sacrifice of a low production of ester volatiles. (C) 2012 Elsevier B.V. All rights reserved.