Maturity Indices Apple Fuji
- Ground Apple Fuji color change from green to light-green or white may provide a useful indicator for harvest.
- Fruit should be harvested before starch degradation is complete
- Limited research indicates that fruit harvest should occur by 180 to 190 days from full bloom to reduce postharvest disorders (skin cracking and internal browning).
- 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, cracks in the skin (checking), bitter pit, insect injury, etc.
- Percent blush on the apple.
Apple Fuji Optimum Temperature
0 ± 1°C (32 ± 2°F)
Apple Fuji Optimum Relative Humidity
90 to 95%
Apple Fuji Rates of Respiration
4 to 6 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
2 to 4 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 Fuji apples:
<0.5% carbon dioxide (see note)
1.5 to 2.0% oxygen
- maintains firmness and acidity
- reduces susceptibility to bitter pit and storage scald
- can store up to 8 months in CA
Note: Late harvested Fuji apples (beyond 180 days from bloom) should not be placed in CA storage. Even at 0.5% CO2, internal browning can develop.
Information is incomplete; however, Fuji apples appear to be slightly to moderately susceptible to scald. However, earlier harvested fruit will be more susceptible to scald. DPA may be needed for storage in air for longer than 2 months. CA storage reduces scald incidence.
Bitter pit has been observed on a small percentage of fruit. Early harvested, large fruit from young, vigorous trees are most susceptible. Preharvest calcium sprays are most effective to reduce bitter pit. Postharvest calcium dips are also beneficial.
Calcium Rates for Postharvest Dips
2 to 3% solid flakes (77% CaCl2)
1.5 to 2% calcium chloride (CaCl2)
0.5 to 0.8% calcium ion (Ca+2)
Browning in the apple flesh as a result of carbon dioxide injury. Keep CO2 in storage below 0.50% and do not place apples harvested beyond 180 days from bloom in CA storage.
Skin Cracking or Checking.
Fuji apples appear to be susceptible to skin cracking. The cause is not yet known, however, symptoms increase in severity with delayed harvest.