Development of Orange Peel-Derived Alginate-Pectin Edible Coatings with Chitosan and Clove Essential Oil for Postharvest Preservation of Cherry Tomatoes

Abstract

Postharvest losses of fresh produce remain a major global challenge, with fruits and vegetables estimated to suffer losses of 20-40% worldwide. This study developed sodium alginate-based edible coatings incorporating pectin and bioactive compounds derived from orange peel, chitosan, and clove essential oil for postharvest preservation of cherry tomatoes. Orange peel was utilised as a dual-purpose raw material for simultaneous extraction of pectin and bioactive compounds, supporting a sustainable dual valorisation strategy aligned with circular bioeconomy principles. The use of chitosan significantly reduced film moisture content, indicating denser polymer network formation with lower water retention. FTIR analysis indicated intermolecular interactions among alginate, pectin, chitosan, and clove oil components through hydrogen bonding and electrostatic interactions. Mechanical analysis demonstrated that formulation modifications had minimal effect on Young's modulus but significantly influenced peak force values, suggesting alterations in structural integrity and fracture resistance of the films. Incorporation of clove essential oil in F3 substantially improved DPPH radical scavenging activity relative to F1 and F2, and showed the highest total phenolic content (TPC) on a wet-weight basis, with the best overall visual quality among coated formulations observed when stored at 4 °C for 15 days. The uncoated control developed visible mould growth during storage. The developed coating systems show potential as sustainable alternatives for enhancing postharvest quality and extending the storage stability of fresh cherry tomatoes, pending quantitative postharvest validation.