Polysaccharide-based layer-by-layer edible coatings for shelf-life extension of fresh tomatoes

Abstract

High yield loss in tomatoes due to suboptimal post-harvest handling and storage demands innovation in preservation technology that is effective and environmentally friendly. Here, we develop polysaccharide-based layer-by-layer edible coatings made of chitosan and hydroxypropyl methylcellulose (chitosan/HPMC) and evaluate their effectiveness for extending the shelf-life of fresh tomatoes using three different application methods (i.e., dipping, air-gun spraying, and manual air-pressure spraying). The coating films are formulated and characterized based on physical, mechanical, and permeability properties. The coated tomatoes have a significantly improved storability of 12 days longer than their uncoated counterpart. Among the investigated application methods, air-gun spraying proves to be the most effective, consistent, and practical method for implementing chitosan/HPMC layer-by-layer on fresh tomatoes. It can limit final weight loss to 7.27%, maintain firmness at 5.44 MPa, and retain ∼68% of the total soluble solids after 24 days of storage. These findings provide an important foundation to design efficient edible coating strategies for sustainable post-harvest preservation.