Valorizing mango (Mangifera indica) peel and kernel extracts as sustainable edible coatings for preservation of fresh strawberries (Fragaria × ananassa)

Abstract

Coatings play an imperative role in increasing the shelf life of strawberries and have the potential to minimize post-harvest losses. In this study, the impact of coating formulated from starch, isolated from mango kernel and bioactive compounds, extracted by using three different techniques (conventional solvent extraction, microwave-assisted extraction, and ultrasonic-assisted extraction) and solvents (distilled water, ethanol, and hydro-alcohol) was evaluated. Microwave-assisted extraction using hydro-alcohol resulted in the highest total phenolic content (36.77 mg gallic acid equivalents [GAE]/g), total flavonoid content (23.81 mg QE/g), antioxidant activity (84.78%), and total carotenoid content (9.58 mg/g). Starch-based coating was analyzed for various physico-chemical properties like yield (40.73 ± 0.97%), amylose content (36.68 ± 0.05%), swelling power (16.81 ± 0.03 g/g), solubility power (1.54 ± 0.12 g/g), and gelatinization power (72 ± 3.57 °C). Thus, the effects of edible coating concentrations (2, 4, and 6%) and bioactive compounds (0.5, 1.0, 1.5, and 2.0%) were effective for prolonging the shelf life of strawberries during the storage period. Lowest decrease (12.66, 0.47%, 1.59 mg GAE/g, and 1.96 × 10 4 colony-forming unit (CFU)/g) in physiological weight loss, titratable acidity, total antioxidant activity, and microbial count was recorded in 4% starch, and the highest (19.30, 0.40%, 1.52 mg GAE/g, and 3.40 × 10 4  CFU/g) decrease was recorded in 2% starch. Therefore, the combined effect of starch and bioactive compounds can be integrated into the supply chain management of strawberry fruit to extend storage life, retain maximum quality attributes, marketability, and maintain quality during transport and storage. Coatings are proven to be feasible due to their edible, non-reactive, and biodegradable nature.