RESPONSES OF BRITISH COLUMBIA-GROWN APPLES TO LOW-OXYGEN AND LOW-ETHYLENE CONTROLLED ATMOSPHERE STORAGE

Golden Delicious (GD), Red Delicious (RD), Spartan (SP), and McIntosh (MC) apples (Malus domestica Borkh.) from commercial sources kept well in a rapidly established 1.0% O₂ + 1.0%–1.5% CO₂ atmosphere at 0.5°C (GD,RD,SP) or 3.0°C (MC). Incidence of skin injury was high in SP and MC, low in RD (purple-brown discoloration), and negligible in GD (brown lesions) held in 0.5% O₂ + 1.0%–1.5% CO₂. Progression of skin discoloration in MC and SP during subsequent holdings in 0°C and 20°C air was cultivar-dependent.

Firmness benefits from removal of ethylene in the storage atmospheres (GD,RD,SP: 1.5% O₂ + 1.5% CO₂, 1.5°C; MC: 2.2% 0₂ + 3.0% CO₂, 1.7°C) was of no commercial significance. After storage and shelf-life test, MC held in 1.0% 0₂ + 1.0% CO₂ at 2.9°C (LO) with high levels of ethylene were firmer than those held in 2.2% 0₂ + 5.0% CO₂ at 1.7°C (HO) with either high (HE) or low (LE) levels of ethylene but the incidence of storage disorder was lower than that in HO-HE fruit and comparable to that in HO-LE fruit. Ethylene scrubbing suppressed ethylene-forming-enzyme activity and improved flesh firmness in preclimacteric but not postclimacteric MC apples.