Fruit Produce Facts English

Jujube, Chinese (Chinese date)

Recommendations for Maintaining Postharvest Quality

Adel A. Kader

Department of Plant Sciences, University of California, Davis

Maturity & Quality

Maturity Indices

Change in color is the main maturity index for Chinese jujube (Zizyphus jujuba). If picked green they do not ripen satisfactorily off the tree. Color changes from green to whitish-green to reddish-brown to dark-brown as the jujubes ripen. They should not be picked before the whitish-green stage.

Quality Indices

Jujubes are round to oblong drupes (2-5 cm in diameter, depending on cultivar) and have a spongy, subacid and sweet-tasting pulp. They can be eaten fresh, dried, or candied and are a very rich source of vitamin C. Compared with other fruits fresh jujubes are lower in water content (70-75%) and titratable acidity (0.15-0.25%), but higher in soluble solids (21-23%), total sugars (20-22%), phenolics (0.2-0.3%), and ascorbic acid (400-600mg/100g fresh weight).

Maturity & Quality Photos

Title: Ripeness Stages

Photo Credit: Don Edwards, UC Davis

Temperature & Controlled Atmosphere

Optimum Temperature

3-10°C (38-50°F) for fresh jujubes (storage potential = 2-3 months)

3-20°C (38-68°F) for dried jujubes (can be stored for up to one year)

Optimum Relative Humidity

75-85% for fresh jujubes (70-75% moisture)

55-60% for dried jujubes (20-25% moisture)

Rates of Respiration

15-20ml CO₂/kg·hr at 20°C (68°F); nonclimacteric respiratory pattern

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

Less than 0.3 ml/kg·hr at 20°C (68°F)

Responses to Ethylene

Exposure of fresh whitish-green jujubes to 100ppm ethylene for 2-4 days at 20°C (68°F) results in faster and more uniform ripening as indicated by change of color to reddish-brown.

Responses to Controlled Atmospheres (CA)

No published information.

Temperature & Controlled Atmosphere Photos

Title: Ethylene Effects

Photo Credit: Don Edwards, UC Davis

Disorders

Physiological and Physical Disorders

Chilling injury. Fresh jujubes are susceptible to chilling injury (development of sheet pitting, i.e. relatively large sunken areas, on the surface) if kept at temperatures below 3°C (38°F) for longer than two weeks.

Pathological Disorders

Jujubes can be infected with decay-causing fungi (such as Alternaria spp and Botrytis spp.) If they are stressed due to physical damage and/or chilling injury. The best control strategies are avoiding mechanical injuries during harvesting and handling and maintaining the optimum ranges of temperature and relative humidity throughout the postharvest handling system.

Disorders Photos

Title: Chilling Injury

Photo Credit: Don Edwards, UC Davis

Date

February 2000

Use of Materials

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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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