Combined use of physical treatments and edible coatings in fresh produce: moving beyond

Abstract

Purpose of the review: In this review we describe the general principles and recent trends in edible coating of fresh produce. We also discuss some features that may link coating applications with common postharvest physical methods (modified atmospheres, heat treatments and irradiation). Main findings: Coatings of intact and fresh-cut produce must be considered a supplement to proper temperature control. Works aimed at determining the outcome of edible coatings must then compare their benefits under proper postharvest storage conditions (optimal temperatures and high relative humidity with minimal delays). Extensive research has been conducted in the last decade to generate material combinations that would meet the specific needs for coating fruits and vegetables. Substantial improvements in the materials properties (eg, through the evaluation of novel matrix constituents and functional ingredients, as well as by developing multilayer, blended or nanocomposite materials) are still possible. In spite of their relative long history as treatments to reduce deterioration and their joint categorization as environmentally-friendly approaches, coating technologies and postharvest physical methods have evolved quite independently. Combined developments may be useful to increase their positive effects. Rather than simply adding the improvements of different treatments applied sequentially, we argue that active collaboration between researchers working on postharvest physical treatments and edible coatings offers opportunities to develop better and innovative approaches that maximize the benefits on quality maintenance. Directions for future research: Innovative approaches superseding the additive effects of combining coatings and physical treatments are needed. One area to be explored more deeply is the application of physical treatments during or after coating formation, which may improve the material´s properties, while inducing hormetic responses in the commodities. Coatinginduced modified atmospheres need to be revisited and improved. The feasibility of using mild post-coating physical treatments to induce custom changes in the materials and to facilitate the release of active principles also requires further work. Finally, research aimed at solving technical difficulties arising during scaling-up processes may help to facilitate the transfer of coating applications from academia to industry.