Changes in Ethylene, Acids, and Brown-core Development of ‘Bartlett’ Pears in Low-oxygen Storage

Ethylene production of ‘Bartlett’ pears ( Pyrus communis L.) was suppressed by 1 % O 2 during storage at − 1°C. Elevated CO 2 concentrations further suppressed ethylene production. Organic acids were retained at higher levels in fruits stored in 1% O 2 than in those stored in air, and elevated CO 2 concentrations in 1% O 2 -enhanced acid retention. Both malic and citric acids decreased linearly during 8 days of ripening at 20° regardless of previous storage conditions. The suppression of ethylene production and the retention of organic acids implied a beneficial effect of elevated CO 2 in storage of ‘Bartlett’ pears at 1% O 2 . Fruit stored in 1% O 2 at −1° for 4 months developed brown-core regardless of CO 2 levels in the storage, but the incidence of the disorder was enhanced when CO 2 level in the storage was ≥2%. This preliminary study indicated that ‘Bartlett’ pears grown in the Hood River district of Oregon could be stored at −1° for 4 months in 1% O 2 with CO 2 at <1.5% with a minimum risk of brown-core development.