Coatings in Hass avocados: advances and limitations

October 1, 2026

For an avocado exporter, preserving fruit quality during transportation is a central part of the business. Coatings applied to the skin are intended to contribute to this objective.

Ricardo Acha, general manager of PROYECTA asociados, in Peru, in his column for Avobook, argues that these coatings should be understood as a preservation tool. Their relevance increases during maritime journeys which, as he points out, can extend to 30 or 40 days.

Transit times vary depending on the port and service. PROMPERÚ records 25 days of transit between Callao and Rotterdam, while MSC announced in 2024 connections from Paita of 18 days to Rotterdam and 14 days to Philadelphia, via Panama.

For China, COSCO reports a transit time of 23 days on the direct Chancay–Shanghai route. These references correspond to the maritime journey, to which the other stages of the commercial chain must be added.

“Coatings are not just about aesthetic shine,” he maintains. For the specialist, their development aims to preserve the condition of the fruit from the packing facility to the consumer, in combination with refrigeration and atmosphere management during transportation.

A barrier that must allow the fruit to breathe

According to Acha, coatings seek to reduce water loss, regulate gaseous exchange, and, in certain formulations, contribute to disease control. Results depend on the materials used and the conditions of application and storage.

Lipid- or wax-based formulations seek to reduce water vapor loss. Other coating properties allow the passage of oxygen and carbon dioxide to be modified, with the aim of slowing processes associated with ripening and preserving firmness.

However, limiting gas exchange requires a balance. The University of California, UC Davis, notes that controlled atmospheres can delay avocado softening, although it warns that excessive carbon dioxide concentrations, especially with very low oxygen levels, can promote color changes and undesirable flavors. Although this reference corresponds to controlled-atmosphere storage, it helps explain why regulating respiration requires precise conditions.

Therefore, a coating should be evaluated based on its ability to preserve the fruit while allowing it to subsequently ripen with suitable quality for consumption.

Improvement in one attribute does not necessarily imply improvements across all indicators. A study published in Foods in 2026 evaluated coatings made from avocado by-products on Hass fruit. Although the treatments better preserved firmness at some stages of the trial, they did not significantly reduce weight loss compared with uncoated fruit. The result demonstrates the importance of determining what benefits each formulation provides under specific storage conditions.

From physical coating to biological control

Among the approaches highlighted by Acha are plant-based lipids, biopolymers combined with essential oils, and beneficial microorganisms incorporated into a matrix.

In the latter case, he describes a biological competition strategy. Certain selected microorganisms occupy the surface of the fruit and may limit the development of pathogens. Acha notes that he participated in a project that allowed him to learn about this alternative and that there are commercial suppliers of solutions and application equipment.

Scientific research provides background on its potential. One study evaluated sodium alginate coatings with the yeast Meyerozyma caribbica to control anthracnose in avocado. The work supports this line of development, although its results correspond to a specific formulation and set of conditions.

Another approach combines film-forming materials with compounds that have antifungal activity. In Hass avocado, for example, chitosan, agar, and thyme oil coatings have been studied, evaluating both the characteristics of the film and changes in fruit respiration and ethylene production.

These studies show that the interest goes beyond creating a surface barrier. The aim is also to integrate preservation and disease-control functions, whose effectiveness must be verified for each application.

Silk as a line of research

Acha includes fibroin, a silk protein, among the emerging alternatives. In his analysis, its application in avocado still requires adjustments and adaptation.

A study published in 2023 evaluated coatings combining modified chitin nanocrystals, fibroin, and active compounds. In fruit artificially inoculated with the fungus that causes anthracnose, a formulation containing melatonin reduced disease severity by 45%, with an effect equivalent to the comparison fungicide under the conditions of the trial.

The result provides evidence regarding a specific combination of materials. It does not allow that performance to be attributed to fibroin alone or the same effect to be anticipated across all commercial operations.

Preserving the quality that comes from the field

For Acha, the choice of a coating should consider the variety and destination market. “Its success depends on the correct combination between the active compound and the substrate matrix,” he explains.

From an operational perspective, this means determining how the fruit responds during storage, transportation, and subsequent ripening. Reducing weight loss or maintaining firmness should be accompanied by an assessment of internal condition and sensory quality at consumption.

The specialist also places a limit on the role of these technologies: “We cannot place all the responsibility on coatings; the quality of all fruit starts in the field.”

According to Acha’s analysis, the opportunity offered by coatings lies in helping preserve that quality throughout the commercial chain. Their value to the exporter will depend on how much they contribute to reducing deterioration and keeping the fruit marketable under the actual conditions of its operation.