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Recommendations for Maintaining Postharvest Quality


Mary Lu Arpaia1 and Adel A. Kader2

Department of Botany and Plant Sciences, Univ. of California, Riverside

Department of Plant Sciences, University of California, Davis

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Publications for this Commodity

Orange PDF

Maturity & Quality

Maturity Indices

Soluble solids/acid ratio of 8 or higher and yellow-orange color at least on 25% of the fruit surface or soluble solids/acid ratio of 10 or higher and green-yellow color on 25% or greater of the fruit surface.

Quality Indices

  • Color intensity and uniformity
  • Firmness
  • Size
  • Shape
  • Smoothness
  • Freedom from decay
  • Freedom from defects including physical damage (abrasions and bruising), skin blemishes and discoloration, freezing damage, chilling injury, and insect damage
  • Flavor quality is related to soluble solids/acid ratio and absence of off-flavor-causing compounds including fermentative metabolites
Temperature & Controlled Atmosphere

Optimum Temperature

3-8°C (38-46°F) for up to 3 months, depending on cultivar, maturity-ripeness stage at harvest and production area. Some Florida-grown cultivars can be kept at 0-1°C (32-34°F). Arizona-grown Valencia oranges should be kept at 9°C (48°F).

Optimum Relative Humidity


Rates of Respiration

Temperature 5°C (41°F) 10°C (50°F) 15°C (59°F) 20°C (68°F)
ml CO2/kg·hr 2-4 3-5 6-12 11-17

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

< 0.1 µl/kg·hr at 20°C (68°F)

Responses to Ethylene

Exposure to 1-10ppm ethylene for 1-3 days at 20-30°C (68-86°F) may be used for degreening oranges. This treatment does not influence the internal quality (including soluble solids/acid ratio) and may accelerate deterioration and decay incidence.

Responses to Controlled Atmospheres (CA)

A combination of 5-10% O2 and 0-5% CO2 can be useful for delaying senescence and for firmness retention but does not have a significant effect on decay incidence and severity, which is the limiting factor to long-term storage of oranges. Fungistatic levels (10-15%) of CO2 are not used because they may result in off-flavors due to accumulation of fermentative metabolites. Commercial use of CA on oranges during storage and transport is very limited.

Temperature & Controlled Atmosphere Photos

Title: Chilling Injury

Photo Credit: Don Edwards, UC Davis

Title: Freezing Damage

Photo Credit: Jim Thompson, UC Davis 


Physiological and Physical Disorders

Chilling injury. Symptoms include pitting, brown staining, and increased decay incidence. Minimum safe temperature depends on cultivar, production area, and maturity-ripeness stage at harvest. Severity of symptoms can be reduced if water loss is minimized (by waxing or film wrapping) and if decay-causing fungi are controlled (by use of fungicides and/or biological antagonists).

Stem-end rind breakdown. Symptoms include shriveling and peel injury around the stem due to aging.

Rind staining. This disorder results from overmaturity at harvest. It can be reduced by preharvest application of gibberellic acid that delays senescence.

Oil spotting (Oleocellosis). Harvesting and handling turgid oranges can result in release of oil that damages surrounding tissues. Thus, oranges should not be harvested when fully turgid such as early in the morning and soon after rain or irrigation.

Pathological Disorders

Important Diseases:

Control Strategies

  • Minimizing physical damage during harvesting and handling
  • Treatment with postharvest fungicides and/or biological antagonists. Also, heat treatments may be used
  • Prompt cooling and subsequent maintenance of optimum temperature and relative humidity throughout marketing operations
  • Removal and/or exclusion of ethylene
  • Effective sanitation procedures throughout postharvest handling

Disorders Photos

Title: Alternaria Rot (1)

Photo Credit: Don Edwards, UC Davis

Title: Alternaria Rot (2)

Photo Credit: Don Edwards, UC Davis

Title: Alternaria Rot (3)

Photo Credit: Don Edwards, UC Davis


Photo Credit: Don Edwards, UC Davis

Title: Blue and Green Mold

Photo Credit: Don Edwards, UC Davis

Title: Blue Mold (1)

Photo Credit: Don Edwards, UC Davis

Title: Blue Mold (2)

Photo Credit: Don Edwards, UC Davis

Title: Botrytis Rot

Photo Credit: Don Edwards, UC Davis

Title: Brown Rot (1)

Photo Credit: Don Edwards, UC Davis

Title: Brown Rot (2)

Photo Credit: Don Edwards, UC Davis

Title: Green Mold

Photo Credit: Don Edwards, UC Davis

Title: Lasiodiplodia Stem -end Rot

Photo Credit: Don Edwards, UC Davis

Title: Phomopsis Stem-end Rot

Photo Credit: Don Edwards, UC Davis

Title: Sour Rot

Photo Credit: Don Edwards, UC Davis

Title: Trichoderma Rot

Photo Credit: Don Edwards, UC Davis


May 1999

Use of Materials

The UC Postharvest Technology Center grants users permission to download textual pages (including PDF files) from this World Wide Web site for personal use or to reproduce them for educational purposes, but credit lines and copyright notices within the pages must not be removed or modified.

Except for these specified uses, no part of the textual materials available on the UC Postharvest Technology Center Web site may be copied, downloaded, stored in a retrieval system, further transmitted or otherwise reproduced, stored, disseminated, transferred or used, in any form or by any means, except as permitted herein or with the University of California's prior written agreement. Request permission from UC Postharvest Technology Center. Distribution for commercial purposes is prohibited.

The information in this fact sheet represents our best understanding of the current state of knowledge at the time of the latest update, and does not represent an exhaustive review of all research results. Links to any of these UC Postharvest Technology Center pages are permitted, but no endorsement of the linking site or products mentioned in the linking page is intended or implied by such a link.

How to Cite

Author(s) names. Initial publication or update date (located at the top). Title. Link to the specific Produce Fact Sheet webpage (Accessed date)

Example: Cantwell, M. and T. Suslow. 2002. Lettuce, Crisphead: Recommendations for Maintaining Postharvest Quality. (Accessed January 18, 2014).

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