Edible films and coatings for postharvest products with reduced humidity

Purpose of review: Reduction of moisture and water activity is part of several transformation processes that are carried out on fruits and vegetables with the goal of obtaining products with either low or intermediate moisture content. These products are characterised by some common preservation problems, including chemical ones such as lipid oxidation, physical ones such as moisture absorption and microbiological related ones. Edible films and coatings have been developed for this type of product as a complement or alternative to the traditional preservation techniques. In this paper, we describe the main problems related to postharvest products with lowered humidity and the use of edible films and coatings as a tool to improve the quality and increase the shelf-life of this type of food. Findings: Edible coatings can be used on postharvest products with reduced humidity as a barrier for moisture, oxygen, lipids or aromas, as carriers of additives (antioxidants, antimicrobials), to impart mechanical integrity or to improve sensorial characteristics. Limitations/implications: The research described in this paper was performed mainly at laboratory scale. The research done at industrial scale is very limited. It is necessary to invest time and resources into scaling up the research carried out at laboratory level. Directions for future research: Future studies should focus on optimising coating formulations to control mass transfer or for active edible films, using edible coatings to improve food processing and scaling-up for industrial applications.