Preserving Appeal

Preserving Appeal

Fresh Florida citrus is well known for its excellent taste and juiciness. However, peel disorders sporadically develop after harvest that make the fruit unmarketable, or even worse, show up upon arrival at destination markets. These can be difficult to mitigate because a wide range of peel disorders can produce similar symptoms, and we often do not fully understand the underlying cause(s). Resulting economic losses can run into the millions of dollars and reduce buyer confidence for future purchases. Some types of peel breakdown, such as oil spotting (oleocellosis), chilling injury (CI), and one type of postharvest pitting (PP) are easier to mitigate because they are more clearly related to specific harvest or postharvest handling practices. For example, PP has been related to low internal oxygen concentrations within warm (>50°F) fruit coated with waxes that restrict gas diffusion (e.g., some shellac-based waxes). Improved cooling practices and the use of coatings with better gas diffusion have reduced the occurrence of PP. CI is caused by holding fruit at low, but non-freezing temperatures during storage and transit. However, modern handling practices have made CI a rare occurrence on Florida citrus.

Other types of peel disorders, such as stem-end rind breakdown (SERB) and general peel pitting are influenced by both pre- and postharvest factors and their occurrence can vary considerably from one season to the next. While the cause(s) of these disorders are not completely understood, they appear to be most related to the water status of the fruit. They may first appear during the winter months, especially after cool and/or windy weather with low relative humidity (RH), and continue into the spring at the end of the dry season and as field temperatures increase. Tree water stress from the lack of rain or insufficient irrigation before harvest can significantly increase peel breakdown after harvest. Conversely, application of an antitranspirant (e.g., 1% or 2% Vapor Gard) to the trees decreases the permeability of the fruit cuticle to water loss and reduces postharvest peel breakdown.

Health Factors

Plant nutrition, especially low potassium (K), also has been associated with peel disorders in citrus fruit such as creasing and pineapple orange peel pitting. Potassium plays an important role in osmotic (water potential) regulation of cells and in regulating stomatal closing. Recently, we found a single preharvest foliar application of mono-potassium phosphate (0-52-34; 23.5 lb. MKP per acre; 8 lb. K2O per acre) can often significantly reduce postharvest peel breakdown. Thus, before harvest, it is important to maintain an adequate supply of water to the trees and consider a preharvest foliar K or an antitranspirant spray if the block has a history of developing peel disorders.
 
After harvest, drying conditions that promote peel breakdown arise from delays in packing, holding the fruit under low RH and high temperatures, and excessive air movement around the fruit. Studies by Dr. Jacqueline Burns’ group (UF/IFAS) and others worldwide have shown that postharvest fruit exposure to low RH conditions (i.e., 30%) for as little as a few hours, followed by high RH (e.g., 90%) conditions induces peel pitting. Even low RH conditions in the field at harvest can result in greater pitting of the fruit after harvest. Excessive brushing during packing also increases water loss and enhances peel breakdown.

Time And Care

After harvest, the best way to prevent peel breakdown is to minimize the time between harvest and waxing, especially during hot, dry, or windy weather, and to keep the fruit continuously under high RH conditions (>90%). Avoid warm temperatures because even with the same RH, warmer air dries fruit faster. During packing, avoid excessive brushing that increases water loss, keep brush speeds below 100 rpm, and use automatic wipeouts to prevent fruit from sitting idle on the brushes. Cool the fruit as soon as possible and maintain low (but non-injurious) temperatures throughout storage, transport, and marketing.

Leave a Reply

Featured Stories

VegetablesSeminis Hosts Growers For Its 2014 Southeastern Field Day
December 19, 2014
Seed company showcases new varieties available now and in the pipeline. Read More
CitrusFeed The People With Food And Food For Thought [Opinion]
December 19, 2014
Educating the general public about agriculture is a daunting task that can be accomplished one bite at a time. Read More
CucurbitsNew Product Takes Aim At Nematodes
December 19, 2014
NIMITZ receives EPA and Florida registrations. Read More
Crop ProtectionSuccess Sans Methyl Bromide Could Prove Costly
December 19, 2014
Economic factors must be accounted for when seeking a suitable replacement. Read More
VegetablesEnza Zaden Cuts Ribbon For New Florida Vegetable Research Facility
December 18, 2014
Seed company shows off new digs and new varieties at its Myakka City field station. Read More
VegetablesRispens Seeds Highlights Their Latest Vegetable Varieties
December 18, 2014
For more information, contact: Rispens Seeds 1357 Dutch American Way, P.O. Box 310, Beecher, IL 60401 708-946-6560; 888-874-0241; fax: 708-946-6115 Read More
Protected Agriculture2014 Marks The 50th Anniversary Of The Double-Poly Greenhouse [sponsor content]
December 18, 2014
Double-poly greenhouses revolutionized the greenhouse industry back in the 1960s, opening the way for developments that still impact the industry 50 years later. Read More
CitrusSouthwest Florida Citrus Bus Tour Yields Learning Opportunity
December 18, 2014
Find out what Florida Grower editor Frank Giles saw and heard during Peace River Valley Citrus Growers Association's annual outing. Read More
Fruits6 Food Trends For 2015
December 17, 2014
University of Florida experts predict what will be cooking for the upcoming year. Read More
VegetablesReed’s Seeds Showcases Their Latest Vegetable Variety Offerings
December 17, 2014
For more information, contact: Reed’s Seeds 3334 NYS 215 Cortland, NY 13045 607-753-9095; fax: 607-753-9511 rsjackie@twcny.rr.com Read More

The Latest

VegetablesSeminis Hosts Growers For Its 2014 Southeastern Field D…
December 19, 2014
Seed company showcases new varieties available now and in the pipeline. Read More
CitrusFeed The People With Food And Food For Thought [Opinion…
December 19, 2014
Educating the general public about agriculture is a daunting task that can be accomplished one bite at a time. Read More
CucurbitsNew Product Takes Aim At Nematodes
December 19, 2014
NIMITZ receives EPA and Florida registrations. Read More
Crop ProtectionSuccess Sans Methyl Bromide Could Prove Costly
December 19, 2014
Economic factors must be accounted for when seeking a suitable replacement. Read More
VegetablesEnza Zaden Cuts Ribbon For New Florida Vegetable Resear…
December 18, 2014
Seed company shows off new digs and new varieties at its Myakka City field station. Read More
VegetablesRispens Seeds Highlights Their Latest Vegetable Varieti…
December 18, 2014
For more information, contact: Rispens Seeds 1357 Dutch American Way, P.O. Box 310, Beecher, IL 60401 708-946-6560; 888-874-0241; fax: 708-946-6115 Read More
Protected Agriculture2014 Marks The 50th Anniversary Of The Double-Poly Gree…
December 18, 2014
Double-poly greenhouses revolutionized the greenhouse industry back in the 1960s, opening the way for developments that still impact the industry 50 years later. Read More
CitrusSouthwest Florida Citrus Bus Tour Yields Learning Oppor…
December 18, 2014
Find out what Florida Grower editor Frank Giles saw and heard during Peace River Valley Citrus Growers Association's annual outing. Read More
Fruits6 Food Trends For 2015
December 17, 2014
University of Florida experts predict what will be cooking for the upcoming year. Read More
VegetablesReed’s Seeds Showcases Their Latest Vegetable Var…
December 17, 2014
For more information, contact: Reed’s Seeds 3334 NYS 215 Cortland, NY 13045 607-753-9095; fax: 607-753-9511 rsjackie@twcny.rr.com Read More
CitrusStudy: Florida Citrus Valued At More Than $10 Billion
December 17, 2014
Industry continues to have large impact on the state’s economy. Read More
Apples & PearsNovember Cold May Hurt Washington Orchards
December 17, 2014
But it’s too early to tell if well-below-normal temperatures will increase tree mortality. Read More
NutsAlmond Growers Lose Trees In Storm
December 17, 2014
Last week’s welcome rains in California knocked down trees, especially older ones. Read More
NutsAlmond Conference Draws Record Attendance
December 17, 2014
Nearly 3,000 industry professionals attend 42nd annual event in Sacramento, CA. Read More
Insect & Disease UpdateManage HLB From The Bottom Up
December 17, 2014
Finding the right balance between the roots and shoots is critical to disease mitigation. Read More
VegetablesVariety Trials 2014: Seedway
December 17, 2014
As part of American Vegetable Grower’s (AVG) 2014 variety trial coverage, we visited Seedway’s seed trial at Spiral Path Organic Farm in Loysville, Read More
OrganicUSDA Proposes Expansion Of Organic Assessment Exemption
December 17, 2014
Action would increase the entities exempt from paying assessments for promotion programs on products certified as “organic” or “100% organic.” Read More
MarketingThe U.S. Potato Board Receives $5 Million In Funding To…
December 17, 2014
The funds will be used to help increase consumption of frozen, dehydrated, chip stock, table stock and seed potatoes around the world. Read More