- Ground color Apple Gala change from green to light-green or white may be the most useful indicator of maturity for harvesters.
- Beginning of starch degradation may also indicate harvest time.
- Firmness, crispness, lack of mealiness.
- Flavor, including soluble solids, titratable acidity and flavor volatiles.
- Freedom from defects such as bruising, decay, stem or blossom-end cracks, bitter pit, insect injury, etc.
- Percent blush on the apple (visual quality only).
Apple Gala Optimum Temperature
0° ± 1°C (32 ± 2°F)
Cool rapidly, this apple softens quickly
Apple Gala Optimum Relative Humidity
90 to 95%
Rates of Respiration
6.5 to 8 ml/kg·hr at 0°C (32°F)
To calculate heat production multiply ml CO2/kg·hr by 440 to get Btu/ton/ day or by 122 to get kcal/metric ton/day.
Rates of Ethylene Production
4 to 12 µl/kg·hr at 0°C (32°F)
Responses to Ethylene
Ethylene can accelerate senescence and loss of firmness. A reduction in ethylene concentration may reduce susceptibility to scald.
Responses to Controlled Atmospheres (CA)
The following atmospheres have been successful for Gala apples:
- 1 to 2% carbon dioxide (1.5 to 2% oxygen)
- maintains firmness and acidity
- reduces susceptibility to bitter pit and storage scald
- can store up to 4 or 5 months in CA
- Additional research may determine more optimum atmospheres.