Chitosan/gelatin coating loaded with ginger essential oil/β-cyclodextrin inclusion complex on quality and shelf life of blueberries

Abstract

Blueberries are highly susceptible to fungal pathogens and oxidative deterioration due to their thin epidermal layer, which can be mitigated by applying a natural polymer-based antimicrobial coating to their surface. This study aimed to develop a chitosan/gelatin-based antimicrobial coating utilizing ginger essential oil (GEO) to extend the postharvest quality of blueberries. To ensure GEO's stability within the coating, it was initially encapsulated with β-cyclodextrin (β-CD) using the inclusion complexation technique. The GEO/β-CD inclusion complex (IC) formed rhomboidal shapes with high encapsulation efficiency and small particle sizes. When the optimized GEO/β-CD IC was incorporated into the chitosan/gelatin polymer solution, it significantly increased surface hydrophobicity and free radical scavenging activity, and suppressed the growth of three selected fungi, namely Botrytis cinerea, Penicillium italicum and Alternaria alternaria. The results of postharvest storage quality revealed that blueberry samples coated with CH/Gel-GEO/β-CD IC-5 effectively maintained the quality of blueberries by decreasing weight loss and decay incidence, and regulating anthocyanin and other oxidation-related enzyme activities compared to the control group during 16 days at 25 °C and 40 days at 4 °C storages. In conclusion, it can be stated that CH/Gel-GEO/β-CD composite coating can be a promising technology to address the drawbacks of blueberry preservation.