A new technology that determines low-oxygen thresholds in controlled-atmosphere-stored apples

Abstract

HarvestWatch is a new chlorophyll fluorescence (F)-based technology that identifies the low-oxygen threshold for apple (Malus x domestica) fruit in dynamic low-O2 controlled atmosphere (DLOCA) storage environments [e.g., <1% oxygen (O2)]. Immediately following harvest, 'Cortland', 'Delicious', 'Golden Delicious', 'Honeycrisp', 'Jonagold' and 'McIntosh' fruit were cooled and loaded into 0.34 m3 (12.0 ft 3) storage cabinets. A static controlled atmosphere (CA) regime of 1.5% O2, 1.5% carbon dioxide (CO2) and 3°C (37.4 °F) [0°C (32.0°F) for 'Delicious' and 'Golden Delicious'] was established for the control fruit, while the low-O2 threshold was identified by a spike in the fluorescence parameter, Fα, as the O 2 levels in the DLOCA cabinets were lowered below 1%. The DLOCA storages were then maintained at O2 levels of 0.1% to 0.2% above the threshold value for each cultivar, which returned Fα to prethreshold signatures. Quality.