Respiratory activity and compositional changes in Eksotika papaya fruit following storage in low-oxygen atmosphere

A. R. Abd. Shukor and O. Ahmad Shokri

Abstract

Papaya cv. Eksotika fruit were stored for 4 weeks in 2% and 5% O2 atmosphere, and air (21% O2 ) at 12 °C. The CO2 and ethylene production rates of fruit stored in 2% and 5% O2 were suppressed during storage but recovered after transfer to air at 20 °C. However, the ethylene production recovery was slower in the low-O2 stored fruit than the air-stored fruit. The 2% O2 atmosphere was more effective than 5% O2 in suppressing the ethylene production. The residual effect of low-O2 storage was more apparent on the ethylene than CO2 production rate. Fruit stored in 2% and 5% O2 for 4 weeks attained peak production of CO2 after 3 days,while peak CO2 production was attained in air-stored fruit after 2 days following transfer to air. The respiratory quotient value of about 1 and the absence of ethanol in the headspace gas of fruit that had been stored in 2% and 5% O2 for 4 weeks indicated that anaerobic metabolism was non-existent. The soluble solids and sugar contents of ripe fruit stored in 2% O2 were unaffected even after 4 weeks of storage. Extending the storage period from 1 to 4 weeks in low-O2 atmosphere resulted in a slight reduction in the a* (red) value of the fruit pulp, while the b* (yellow) value was insignificantly different between the low O2 and the air-stored fruit.

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