Active Edible Coatings to Mitigate Postharvest Diseases Causing Waste of Blueberries, Strawberries, and Cherry Tomatoes

Abstract

Packaging can help prolong the shelf life of perishable agrifoods. In the present investigation, edible coatings were tested to reduce food waste caused by filamentous fungi and increase the shelf-life of high-value products such as strawberries, tomatoes, and blueberries. Different combinations of sodium alginate and calcium chloride, and various immersion times were tested on tomato as a model. The ability to activate edible coatings with food-grade compounds/extracts, such as sodium bicarbonate or Moringa oleifera extract (MLE), was explored. The extract was also tested in vitro against some of the main postharvest pathogens, such as Botrytis cinerea, Alternaria alternata, Rhizopus stolonifer, Colletotrichum acutatum, and Penicillium expansum. The most suitable composition for the edible coating proved to be 2% sodium alginate and 2% calcium chloride. MLE proved not to reduce fungal growth, except for A. alternata and C. acutatum. Concerning active coatings, particularly those containing MLE, there was a reduction in the incidence of rots on strawberries (−45%) and tomatoes (−59%) as compared to the uncoated control. Furthermore, a reduction in the severity of rots was recorded in all tested fruits (−73% in tomato, −88% in strawberries, −47% in blueberries) as compared to the uncoated control. The active edible coatings could play a role in reducing rots, contributing to the extension of the shelf-life of the selected products.