The effects of storage atmosphere on the keeping quality of ‘Idared’ apples

SummaryThe response of ‘Idared’ apples to storage in atmospheres containing less carbon dioxide than the recommended 8% was investigated after it was found that core flush could develop in 8% CO2 + 13% O2 at 3.5°C. Storage in <1 % CO2 and 1 or 2% O2 resulted in less core flush than storage in 5% CO2 + 3% O2, but apples from 2% O2 were softer, as determined by both a sensory panel and a penetrometer, than those from 5% CO2 + 3% O2. Jonathan spot developed in both low oxygen regimes. A pre-harvest application of daminozide increased the surface area coloured red, increased firmness at harvest and reduced the incidence of core flush in samples stored in 8% CO2 + 13% O2. It was concluded that to minimize losses from physiological disorders, ‘Idared’ grown in UK should be picked no later than the beginning of November and stored in <1% CO2 +1% O2 for no more than three months.