Storage humidity and post-storage handling temperature affect bruising and other apple quality characteristics

In a 2-year study, 'McIntosh' apples were stored in a CA regime of 2.5% O-2 + 4.5% CO2. Within the CA cabinets there were three relative humidity (RH) levels: low (> 75% RH, CaCl2 salt in the chamber), ambient (> 90% RH), or high (> 95% RH, distilled water in the chamber). After removal at 4 and 8 months, the fruit were warmed to handling temperatures of 0 degreesC, 10 degreesC, or 20 degreesC and subjected to three levels of compression bruising of 0, 45, or 90 N on the red and green sides of the fruit with a penetrometer using a 1.5 x 1.5-cm tip. Bruising was always more visible on the green than the red side. Low-RH CA storage decreased visible bruising, compared with ambient-RH and high-RH CA. Although visible shrivel was not observed, the low-RH treatment may increase the possibility of its occurrence. Surprisingly, both respiration and titratable acidity (TA) loss were lowest in the low-RH, compared with the ambient-RH and high-RH CA storage. Increasing the temperature during post-storage handling decreased the amount of visible bruising.