DEVELOPMENT OF ACTIVE COATING INCORPORATED WITH NANOEMULSIFIED CINNAMON ESSENTIAL OIL (Cinnamomum cassia) TO INHIBIT Colletotrichum spp. GROWTH

Cinnamon essential oil (CEO) has antioxidant and antimicrobial properties and can be incorporated into coatings to increase fruit shelf life. Active coating can be applied to control or reduce post-harvest diseases such as anthracnose. In this sense, this study aimed to evaluate the properties of a CEO-incorporated in a polymeric coating. For this purpose, a nanoemulsion of CEO (NECEO), in the proportion 1:1 (w/w) of CEO and Tween 80, was prepared in ultrasound (150W/3min) and slowly incorporated into a polymeric blend with final formulation (w/w): 1% sodium alginate crosslinked with calcium chloride, 0.5% sodium carboxymethylcellulose, 0.25% CEO, 0.25% Tween 80 and 0.3% glycerol. NECEO and the coating activated by NECEO were characterized for oil droplet size (Z-Average), polydispersity index (PDI), and stability (room temperature for 30 days / 50 ºC for 48 hours / after centrifugation at 9,000 rpm for 20 minutes). Finally, the antifungal capacity of these emulsions against the anthracnose agent, Colletotrichum spp. (10-5 conidia/mL), was determined. Oil droplet size and PDI values for NECEO and the coating were, respectively: 60.35 ± 0.5nm/0.2 ± 0.0 and 158.2 ± 7.57nm/0.7 ± 0.0. Increased NECEO oil droplets on the coating were associated with increased PDI, which is likely caused by the presence of other coating components. This phenomenon is being investigated. Both NECEO and the coating showed no signs of phase separation in stability tests. This reinforces the hypothesis that the size results may be affected by other coating components, as nanoemulsions (<200nm and PDI between 0.2 and 0.5) are considered resistant to phase separation and stable. NECEO and the active coating inhibited the growth of Colletotrichum spp. by 100% and 91.7%, respectively, demonstrating the samples’ high antifungal activity. Data reveal the potential of coatings activated by NECEO to inhibit the progression of anthracnose and therefore prevent post-harvest fruit losses.