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Pawpaw

Recommendations for Maintaining Postharvest Quality

Paw Paw

Douglas D. Archbold1 and Kirk W. Pomper2
1Department of Horticulture, University of Kentucky
2Atwood Research Center, Kentucky State University

Maturity & Quality

Pawpaw (Asimina triloba; family Annonaceace) is the largest edible fruit native to the eastern U.S. The fruit ripens between mid August and mid October, depending on genotypes and growing location.

Maturity Indices

The only way to detect if ripening has commenced is to gently press or squeeze the fruit to determine if softening is evident. Some cultivars exhibit a change in skin color from darker to lighter green or even to yellow, and some also exhibit some skin browning or darkening at more advanced stages of ripening. Flesh may be cream-colored, yellow, or light orange, depending on cultivar, when fully ripe. Ripening is accompanied by an increase in soluble solids including sugars (sweetness) and significant aroma production. Pawpaws should be picked when flesh softening is first evident, as they ripen rapidly and become too soft to handle within 3 to 5 days.

Quality Indices

  • Green to yellowish-green skin, firm fruits with minimal brown discoloration on the skin.
  • Soft, custard-like flesh
  • Sweetness (glucose, fructose and sucrose) at >18-20% soluble solids
  • Intense aroma reminiscent of banana, mango, and/or pineapple.
  • Free of bruises and decay

Maturity & Quality Photos

Title: Pawpaw genotype #1-23

Photo Credit: Kirk W. Pomper, University of Kentucky, Lexington

Title: Pawpaw genotype #2-7

Photo Credit: Kirk W. Pomper, University of Kentucky, Lexington

Title: Pawpaw genotype #7-90

Photo Credit: Kirk W. Pomper, University of Kentucky, Lexington

Title: Pawpaw genotype #8-2

Photo Credit: Kirk W. Pomper, University of Kentucky, Lexington

Title: awpaw genotype #G4-17

Photo Credit: Kirk W. Pomper, University of Kentucky, Lexington

Title: Pawpaw genotype #K1-79

Photo Credit: Kirk W. Pomper, University of Kentucky, Lexington

Title: Pawpaw genotype #NC-1

Photo Credit: Kirk W. Pomper, University of Kentucky, Lexington

Title: Pawpaw genotype (PA-Golden)

Photo Credit: Kirk W. Pomper, University of Kentucky, Lexington

Title: Pawpaw genotype (Shenandoah)

Photo Credit: Kirk W. Pomper, University of Kentucky, Lexington

Title: Pawpaw genotype (Taytwo)

Photo Credit: Kirk W. Pomper, University of Kentucky, Lexington

Title: Pawpaw genotype (Zimmerman)

Photo Credit: Kirk W. Pomper, University of Kentucky, Lexington

Temperature & Controlled Atmosphere

Optimum Temperature

0-4°C (32-40°F) for a maximum of 4 weeks

Lower temperatures within this range and especially longer periods of cold storage may induce chilling injury.

Optimum Relative Humidity

90-95%

Rates of Respiration

Respiration at harvest may be 50-100 mg CO2/ kg•hr at 20°C (68°F), and may increase 2- to 5-fold to a peak within 3 days.

Rates of Ethylene Production

Ethylene production at harvest may be 1-4 µg/kg•hr at 20°C (68°F), and it may increase to 5-15 µg/kg•hr within 3 days.

Pawpaw exhibits increasing respiration and ethylene production with peak values within 3 days after harvest indicating it is a climacteric fruit.

Responses to Ethylene

Field and laboratory studies to date using chemicals, atmospheric modification, or heat treatments that have been effective at modifying ripening behavior in many climacteric species via effects on ethylene biosynthesis or action have failed to appreciably alter ripening of pawpaw.

Responses to Controlled Atmospheres (CA)

There is no information on their response to CA storage.

Temperature & Controlled Atmosphere Photos

Title: Pawpaw genotype #8 20 Intact at Harvest

Photo Credit: Federica Galli, University of Kentucky, Lexington

Title: Storage Effects, X-Cut at Harvest

Photo Credit: Federica Galli, University of Kentucky, Lexington

Title: Storage Effects, Intact at 4 weeks + 72 hrs 4°C

Photo Credit: Federica Galli, University of Kentucky, Lexington

Title: Storage Effects, Intact at 4 weeks 4°C

Photo Credit: Federica Galli, University of Kentucky, Lexington

Title: Storage Effects, Intact at 8 weeks + 72 Hrs 4°C

Photo Credit: Federica Galli, University of Kentucky, Lexington

Title: Storage Effects, Intact at 8 weeks 4°C

Photo Credit: Federica Galli, University of Kentucky, Lexington

Title: Storage Effects, X-Cut at 4 weeks + 72 hrs 4°C

Photo Credit: Federica Galli, University of Kentucky, Lexington

Title: Storage Effects, X-Cut at 4 weeks 4°C

Photo Credit: Federica Galli, University of Kentucky, Lexington

Title: Storage Effects, X-Cut at 8 weeks + 72 Hrs 4°C

Photo Credit: Federica Galli, University of Kentucky, Lexington

Title: Storage Effects, X-Cut at 8 weeks 4°C

Photo Credit: Federica Galli, University of Kentucky, Lexington

Disorders

Physiological and Physical Disorders

Chilling Injury. Both skin and internal flesh browning of pawpaw have been observed by 6 weeks at 0-4°C (32-40°F).

Physical Injury. Similar to wound-induced browning in banana, pawpaws can be bruised during ripening. Thus, gentle handling to minimize bruising is essential to reducing postharvest losses.

Shriveling. Symptoms become visible by 6 weeks of cold storage.

Pathological Disorders

Postharvest diseases of pawpaws from Cladosporium spp. and Fusarium spp. have been observed by 6 weeks of 0-4°C (32-40°F) storage.

Date

October 2008

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.

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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