Incorporation of clove essential oil nanoemulsion in chitosan coating to control Burkholderia gladioli and improve postharvest quality of fresh Tremella fuciformis

Abstract

Fresh Tremella fuciformis is becoming more popular among consumers as an edible fungus, as it is more natural and nutritious than dried T. fuciformis. However, fresh T. fuciformis is susceptible to contamination by Burkholderia gladioli leading to deterioration in quality and safety. In this study, clove essential oil nanoemulsions (CNE) were prepared and then incorporated into chitosan coating (CSC) to develop a clove essential oil nanoemulsion/chitosan coating (CNE-CSC) for bacteriostatic and preservation of fresh T. fuciformis. The results showed that CNE-CSC significantly inhibited the growth of B. gladioli with the inhibition rate >85% when the concentration was 1.25 g/L and inhibited more than 85% of biofilm formation when the concentration was as low as 0.625 g/L. The inhibitory activity of CNE-CSC for the growth of B. gladioli directly lowered the expression of bongkrekic acid and then reduced the threat posed by bongkrekic acid to food safety. Moreover, in B. gladioli infection models, CNE-CSC treatment significantly prolonged the preservation of fresh T. fuciformis by preventing B. gladioli from infecting models. Therefore, CNE-CSC could be used as a safe, non-toxic, edible and new preservative coating for fresh T. fuciformis.