ISHS Acta Horticulturae 326: International Symposium on Pre- and Postharvest Physiology of Pome-fruit
VERY LOW OXYGEN STORAGE IN RELATION TO ETHANOL PRODUCTION AND CONTROL OF SUPERFICIAL SCALD IN BRAMLEY'S SEEDLING APPLES |
| Authors: | D.S. Johnson, C.J. Dover, K. Pearson |
| Abstract:
Bramley apples have been traditionally stored in unscrubbed CA conditions of 9% CO2 + 12% O2 (9/12), where they are susceptible to scald after about four months storage. Although storage in low oxygen with elevated carbon dioxide, e.g. 5% CO2 + 1% O2 (5/1), or ethene removal from unscrubbed stores retards scald development, these are expensive technologies but may be necessary should the post-harvest application of chemical antioxidants be discontinued. An investigation was carried out on the effect of storing Bramley apples in low (0.2–1.0%) oxygen with carbon dioxide removed completely by hydrated lime. This method of carbon dioxide removal is commonly used for the storage of Cox apples in the U.K. and dispenses with the need for an external scrubber since hydrated lime can be included with the fruit inside the store. Storing in 0.2% oxygen was too low to support aerobic respiration as evidenced by an immediate build-up of ethanol in the fruit. In 0.4 and 0.6% O2 fruit respired normally for 150 days but ethanol accumulated thereafter. Retardation of scald development by 0.4 and 0.6% O2 was as effective as 5/1 and ethene removal from 9/12 storage, providing scald-free fruit for 216 days. However, rapid loss of firmness occurred in fruit stored in all low oxygen (nominal 0% CO2) conditions after 100 days of storage and was the major limitation to storage life. U.K. Bramley growers will need to pursue scrubbed low oxygen storage, e.g. 5/1 and ethene removal from scrubbed/unscrubbed CA stores as alternatives to the use of chemical antioxidants for the control of scald. | |
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