Chitosan-based active coating for pineapple preservation: Evaluation of antimicrobial efficacy and shelf-life extension

Pineapple is a tropical fruit that is the most economically significant member of the Bromeliaceae family that are rich in flavonoids, phenolic acids, and antioxidants, which protect human cells from free radicals known to cause chronic diseases. However, short postharvest shelf-life of the fruit limits its long-distance distribution and consumption. Chitosan is a positively charged polysaccharide consisting of N-acetyl d-glucosamine and d-glucosamine units that can be used as a promising sustainable biopolymer for active coating of the fruit. In this work, chitosan-based nanocomposite formulations were prepared with added eugenol (clove essential oil) and Aloe vera gel as antioxidant, antibacterial and antifungal agents. The results showed that the incorporation of eugenol oil nanoemulsion and Aloe vera gel in the coatings enhanced their physico-chemical and functional properties including antimicrobial activities against four foodborne bacterial pathogens (Escherichia coli, Alcaligenes faecalis, Staphylococcus aureus, and Bacillus subtilis) and two fungal isolates. The developed coatings not only kept the pineapple fresh, but also preserved its quality and prolonged their shelf-life by up to three weeks during storage in ambient conditions.