Ethanol Accumulation and Poststorage Quality of ‘Delicious’ Apples During Short-term, Low-O2, CA Storage

Abstract

‘Delicious’ apples (Malus domestica Borkh.) harvested on two dates and stored in controlled atmospheres (CA) from 0.0% to 1.5% O 2 were analyzed biweekly during a 14-week storage period for tissue ethanol and other quality parameters. After 14 weeks, ‘Delicious’ fruit stored in 0.0% O 2 was significantly firmer, lower in soluble solids, and had 10 times more ethanol than fruit stored in 0.5% to 1.5% O 2 . Upon return to ambient air for 7 days following low-O 2 storage, up to 50% of the ethanol accumulated was lost. The first external symptoms of low-O 2 injury appeared after 8 weeks in 0.0% O 2 followed by a week in air. Symptoms were associated with ethanol contents >2500 μg·liter −1 . Fruit harvested 7 Oct. produced more ethanol than fruit harvested 23 Sept. (i.e., greater concentration and faster rate). There were no differences in firmness, soluble solids, and titratable acidity due to harvest date.