Development of edible food coating using cassava starch/agar blends infused with clove oil for the preservation of mangoes

Abstract

Food coatings incorporating natural compounds are increasingly recognized for their effectiveness in preserving fresh produce from post-harvest decay and extending its shelf life. In this study, an edible bioplastic food coating was developed using cassava starch, agar and clove oil (CO) for the preservation of tropical fruits, specifically mango. The physicochemical and mechanical properties, water vapor transmission rate (WVTR), moisture absorption, solubility, biodegradability, carbon dioxide evolution, antimicrobial efficacy and tensile strength of the bioplastic were characterized. The bioplastic coating with high starch content (0.5% starch) enhanced WVTR, moisture absorption, water solubility and biodegradability due to the hydrophilic nature of starch and glycerol. Contact angle measurements showed the top surface with a value of 55.87° and the bottom surface with 45.66°. The side with the lower contact angle corresponded to increased water absorption and a higher WVTR. Peeled mangoes coated with starch-rich bioplastic exhibited accelerated water loss and improved retention of vitamin C. Incorporating CO-containing eugenol into the formulation provided antimicrobial effects, which decreased fruit fly oviposition during sun drying and as a result, minimized post-harvest losses. The biofilm also demonstrated adequate tensile strength and received favorable sensory evaluation scores. These properties make it a promising alternative to traditional plastics.