Chitosan-based Layer-by-layer Edible Coatings Application for the Preservation of Mandarin Fruit Bioactive Compounds and Organic Acids

The layer-by-layer application of biopolymeric coatings to mandarin fruits as a postharvest treatment to improve fruit coating efficacy has been reported. A single 1 % (w/v) chitosan application was evaluated, and polyelectrolyte complexes such as 1.5 % (w/v) alginate/chitosan, 1 % (w/v) hydroxypropyl methylcellulose/chitosan, and 0.2 % (w/v) locust bean gum/chitosan were applied to mandarin fruits. The quality of coated mandarin fruits was observed at temperatures: 20 ± 2 °C (up to 10 days) and 5 °C (up to 28 days). Changes in the fruit metabolism were observed by evaluating bioactive compounds (polyphenolic compounds and flavonoids), antioxidant activity, and organic acids during the preservation of mandarin fruits. All of the tested combinations of layer-by-layer coatings significantly impacted the quality of mandarin fruits throughout storage, both at room temperature and cold storage, respectively. The overall best performance was observed for a layer-by-layer hydroxypropyl methylcellulose/chitosan coating in terms of visual aspects, bioactive compounds, antioxidant activity, and organic acids content.