Fruit Produce Facts English
Recommendations for Maintaining Postharvest Quality
Maturity & Quality
Color (more than 2/3 of fruit surface showing yellow color) and a minimum soluble solids/acid ratio of 5,5 or 6 (depending on production area). Grapefruit do not continue to ripen after harvest so they should be harvested fully-ripe (with good flavor).
Temperature & Controlled Atmosphere
12-14°C (54-57°F) depending on cultivar, production area, maturity-ripeness stage at harvest, and storage and transport duration (up to 6-8 weeks).
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
Less than 0.1 µl/kg·hr at 20°C (68°F)
Responses to Ethylene
Exposure of mature-green grapefruits for 1-3 days to ethylene (1-10ppm) at 20-30°C (68 to 86°F) accelerates loss of green color and appearance of yellow color (degreening). This is accompanied by faster peel senescence and greater susceptibility to decay-causing pathogens.
Responses to Controlled Atmospheres (CA)
Temperature & Controlled Atmosphere Photos
Physiological and Physical Disorders
Chilling injury. Severity of chilling injury depends upon cultivar, maturity and ripeness stage at harvest, production area and season (preharvest cultural practices and weather conditions). Symptoms including pitting, reddish brown discoloration, scald, watery breakdown, off-flavors, and increased decay incidence. Waxing or film wrapping to minimize water loss and use of fungicides (especially thiabendazole) to control decay can reduce severity of chilling injury symptoms. Conditioning at 15-18°C (59-65°F) in air or in air + 10-20% CO2 for 5-7 days can reduce severity of chilling injury symptoms on grapefruits that are subsequently exposed to chilling temperatures, such as those required for quarantine treatments against tropical fruit flies.
Oil spotting (Oleocellosis). Physical stress on turgid fruits may result in breaking of oil cells and release of oil that damages surrounding tissues.
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.