Fruit Produce Facts English
Recommendations for Maintaining Postharvest Quality
Adel A. Kader1 and Mary Lu Arpaia2
1Department of Plant Sciences, University of California, Davis
2Department of Botany and Plant Sciences, University of California, Riverside
Maturity & Quality
Percent of dry matter is highly correlated with oil content and is used as a maturity index in California and most other avocado production areas; minimum dry matter required ranges from 19 to 25%, depending on cultivar (19.0% for 'Fuerte', 20.8% for 'Hass', and 24.2% for 'Gwen').
Florida-grown avocado cultivars have lower oil content and are harvested on the basis of a calendar date (days after full bloom).
Temperature & Controlled Atmosphere
5-13°C (41-55°F) for mature-green avocados, depending on cultivar and duration. 2-4°C (36-40°F) for ripe avocados.
Optimum Relative Humidity
Rates of Respiration
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
Avocado fruits do not ripen on the tree and ethylene production begins after harvest and increases greatly with ripening to > 100µl C2H4/kg·hr at 20°C (68°F).
Responses to Ethylene
Treatment with 100ppm ethylene at 20°C (68°F) for 48 hours (early-season fruits), 24 hours (mid-season fruits), or 12 hours (late-season fruits) induces avocados to ripen in 3-6 days, depending on cultivar and maturity. Ripening indices include flesh softening and change of skin color from green to black in some cultivars such as 'Hass'. Ripe (soft) avocados require care in handling to minimize physical damage.
Responses to Controlled Atmospheres (CA)
Temperature & Controlled Atmosphere Photos
Physiological and Physical Disorders
Chilling injury. Skin pitting, scalding, and blackening are the main external chilling injury symptoms on mature-green avocado kept at 0-2°C (32-36°F) for more than 7 days before transfer to ripening temperatures. Avocados exposed to 3-5°C (37-41°F) for more than two weeks may exhibit internal flesh browning (gray pulp, pulp spot, vascular browning), failure to ripen, and increased susceptibility to pathogen attack. The timing of chilling injury development and its severity depend on cultivar, production area, and maturity-ripeness stage.
Anthracnose. Caused by Colletotrichum gloeosporioides and appears as the fruit begins to soften as circular black spots covered with pinkish spore masses in later stages. Decay can penetrate through the flesh and induce browning and rancid flavor.
Stem-end rot. Caused by Botryodiplodia theobromae and appears as dark-brown to black discoloration which begins at the stem and advances toward the blossom end, finally covering the entire fruit. Dothiorella gregaria is another cause of stem-end rot in ripe avocados.
Control methods include good orchard sanitation, effective preharvest fungicide application, careful handling to minimize physical injuries, prompt cooling to optimum temperature for the cultivar and maintaining that temperature during marketing.
[For more information, see our publication "Fruit Ripening and Ethylene Management", available for purchase using our Publication order form.]
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).