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Mandarin/Tangerine

Recommendations for Maintaining Postharvest Quality

Mary Lu Arpaia¹ and Adel A. Kader²

¹Dept. of Botany and Plant Sciences, Univ. of California, Riverside

²Department of Plant Sciences, University of California, Davis

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Maturity & Quality

Maturity Indices

Color (yellow, orange, and/or red) on 75% of fruit surface and soluble solids/acid ratio of 6.5 or higher.

Quality Indices

Color intensity and uniformity
Size
Shape
Firmness
Freedom from decay
Freedom from defects including freezing injury, chilling injury, insect damage, and scars
Flavor depends upon soluble solids/acid ratio and absence of off-flavors

Temperature & Controlled Atmosphere

Optimum Temperature

5-8°C (41-46°F) for 2 to 6 weeks, depending on cultivar, maturity-ripeness stage at harvest, and decay control treatments used.

Optimum Relative Humidity

90-95%

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	6-10	10-15

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

Responses to Ethylene

Mandarins and tangerines can be degreened by exposure to 1-10 ppm ethylene for 1-3 days at 20 to 25°C (68 to 77°F)
Removal of ethylene from transport vehicles and storage facilities for citrus fruits can help reduce decay incidence

Responses to Controlled Atmospheres (CA)

A combination of 5-10% O₂ and 0-5% CO₂ can delay color changes from green to yellow and other symptoms of senescence, but it is not very effective in decay control. Mandarins do not tolerate exposure to fungistatic CO₂ levels (10-15%). Commercial use of CA is very limited.

Temperature & Controlled Atmosphere Photos

Title: Degreening

Photo Credit: Irv Eaks, University of California, Riverside

Disorders

Physiological and Physical Disorders

Chilling injury. Symptoms include pitting and brown discoloration followed by increased susceptibility to decay. Severity increases with longer exposures to lower temperature below 5°C (41°F).

Oil spotting (Oleocellosis). Harvesting and handling turgid citrus fruits can result in breaking of oil cells and release of oil that damages surrounding tissues.

Aging. Symptoms include shriveling and peel injury around the stem end.

Pathological Disorders

Major Diseases:

Green mold (Penicillium digitatum)
Blue mold (Penicillium italicum)
Phomopsis stem-end rot (Phomopsis citri)
Stem end rot (Lasiodiplodia theobromae)
Brown rot (Phytophthora citrophthora)
Anthracnose (Colletotrichum gloeosporioides)

Control Strategies

Reduce the pathogen population in the environment:

Effective preharvest disease control
Use of chlorine in wash water
Heat treatments
Effective sanitation procedures

Maintain Fruit Resistance to Infection

Minimize mechanical injuries
Use proper ranges of temperatures and relative humidity throughout postharvest handling
Use postharvest fungicides and/or biological antagonists
Avoid exposure to ethylene

Date

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.

http://ucanr.edu/sites/Postharvest_Technology_Center_/Commodity_Resources/Fact_Sheets/Datastores/Vegetables_English/?uid=19&ds=799 (Accessed January 18, 2014).

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