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Apple
'Fuji'
Recommendations for Maintaining Postharvest Quality
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Elizabeth J. Mitcham, Carlos H. Crisosto and Adel A. Kader
Department of Pomology, University of California, Davis, CA 95616
Maturity Indices
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Ground color change from green to light-green or white may provide a useful
indicator for harvest.
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Fruit should be harvested before starch degradation is complete
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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).
Quality Indices
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Firmness, crispness, lack of mealiness
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Flavor, including soluble solids, titratable acidity and flavor volatiles.
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Freedom from defects such as bruising, decay, stem or blossom-end cracks,
cracks in the skin (checking), bitter pit, insect injury, etc.
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Percent blush on the apple.
Optimum Temperature
0 ± 1°C (32 ± 2°F)
Optimum Relative Humidity
90 to 95%
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
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maintains firmness and acidity
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reduces susceptibility to bitter pit and storage scald
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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.
Physiological Disorders
Storage Scald. 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. 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.
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Calcium Rates for Postharvest Dips
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2 to 3% solid flakes (77% CaCl2)
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1.5 to 2% calcium chloride (CaCl2)
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0.5 to 0.8% calcium ion (Ca+2)
Internal Browning. 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.
Pathological Disorders
Core Rot. Fuji is susceptible to core rots, as is it's parent Red Delicious,
because of an open calyx tube. Control measures are unknown at this time,
but sanitation in the orchard appears to be important.
Gray Mold, Blue Mold.
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avoid fruit injury
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sanitize water systems with chlorine
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cool fruit quickly
Mucor rot. Some orchads have Mucor organisms in the soil. Sanitation to keep soil out of drench water is important. Do not place fruit from the orchard floor into storage bins. Chlorine will not control this organism and there are no effective fungicides. Mucor continues to grow slowly even at 0°C
(32°F).
Sanitation of Water Systems
Sanitation of water systems used to handle apples is important. Chlorine
at 50 to 100 ppm is very effective, but the level of available chlorine
and solution pH (7.0) must be monitored frequently and adjusted.
Sodium will accumulate when liquid sodium hypochlorite is used and can
burn apple tissues. We recommend water systems be changed once a day to
reduce the risk of burn to apple skins.
Return to Produce Facts
University of California
One Shields Ave., Davis, CA 95616-8683
Copyright ©1996-2000. All rights reserved
Produce/ProduceFacts/Fruit/fuji.html updated June 30, 2000
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