Carnauba wax enriched with encapsulated plant essential oils into native β-cyclodextrins as an innovative wax coating on citrus fruits

Abstract

The incorporation of encapsulated essential oils (EOs) into postharvest non-edible wax coatings for citrus fruit surfaces is an innovative strategy to enhance the antimicrobial and antioxidant properties of these waxes. A thymol:eugenol (50:50) mix, encapsulated in native β-cyclodextrin, was incorporated into an innovative carnauba wax coating (CW-EOsβCD) applied to the surfaces of fresh mandarins and lemons. Wax without thymol:eugenol served as the carnauba wax control (CW). The quality of mandarins and lemons (weight loss, acidity, pH, soluble solids, surface color, firmness, decay incidence and surface microbial loads) was analyzed throughout cold storage (2 and 8 ºC for mandarins, and 8 ºC for lemons) for up to 30 d, followed by a commercialization simulation at 22 ºC for 5 d. Weight losses in CW-EOsβCD-coated lemons were 1.7 and 3.7 units lower after 30 d at 8 ºC and the subsequent commercialization period, respectively, compared to CW lemons. A similar trend was observed in mandarins. Additionally, CW-EOsβCD reduced firmness loss, maintaining 76 and 45 % higher firmness levels in lemons and mandarins, respectively, compared to CW samples at day 30 at 8 ºC, with similar results after the commercialization period. Overall, physicochemical quality and color of mandarins and lemons remained substantially unaffected throughout refrigerated storage and commercialization. However, decay incidences of CW mandarins and lemons after commercialization (25/38 % for samples previously stored at 8 ºC/2 ºC and 17 %, respectively) were highly reduced (more than 25 units) in CW-EOsβCD samples. Furthermore, microbial loads for mandarins and lemons remained very low (<1 log CFU cm −2 ) across all studied microbial groups (mesophiles, psychrophiles, yeasts and molds). In conclusion, the inclusion of encapsulated EOs within the wax coating (CW-EOsβCD) for mandarins and lemons effectively reduced weight loss, firmness loss and decay incidence while preserving other quality parameters. • Waxes for mandarins and lemons were improved with encapsulated thymol:eugenol. • Thymol:eugenol wax reduced weight losses and decay in the studied citrus fruit. • Firmness loss during fruit storage was reduced with • Thymol:eugenol wax did not affect to the physicochemical quality and colour.