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% O2 for 7 days at 20 °C before ripening was initiated by ethylene. Residual effects of low O2 storage in mature green fruit on ripening and ester biosynthesis in fruit were investigated during ripening for up to 6 d at 20 °C. Concentrations of ethanol in mature green fruit did not change during storage in both 21% and 2% O2 atmospheres, but increased in fruit stored in 0.5% O2. The activities of alcohol dehydrogenase (ADH) in 2% and 21% O2 atmospheres remained very low throughout the storage period, but significantly increased with 0.5% O2. 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 O2 atmospheres were slower than in the control. Fruit stored in low O2 also showed a delayed onset of the climacteric peak. The activities of ADH were lower in the low O2 stored fruit than in the control fruit. Productions of ethyl acetate, isoamyl acetate, and isobutyl acetate were remarkably suppressed by low O2 storage. Alcohol acetyltransferase activity increased gradually with storage time in all treatments, being significantly lower in fruit with low O2 pretreatments. The results indicate that low O2 plus room temperature storage can extend storage life of bananas with the sacrifice of a low production of ester volatiles.

► Storage of mature green banana fruit in a low O2 atmosphere inhibited decay and slowed ripening.
► Ester production and activity of related enzymes during ripening differed according to O2 concentrations.
► Low O2 atmosphere at room temperatures maintained and extended fruit quality.
► There is a high potential for low O2 treatment as a simple and inexpensive postharvest technology for banana fruit.