EDIBLE COATING BASED ON CHITOSAN, GELATIN AND DEEP NATURAL EUTECTIC SOLVENTS (NADES) IN THE POSTHARVEST CONSERVATION OF PAPAYA FRUITS

This research investigated the effect of two deep natural eutectic solvents (NADES) as plasticizers in chitosan and gelatin films, applied as edible coatings in the postharvest conservation of papaya in the soil group (Carica papaya L.). Five treatments were tested: control (uncoated), chitosan-gelatin gels (1:4) (QG) without plasticizer and incorporated with glycerol (QG/Gli), NADES linalool:lactic acid (QG/Li-lat) or NADES linalool:octanoic acid (QG/Li-oct), all with 25% plasticizer. The coatings were manually applied to the fruits by manual spreading (1 mL/fruit). Then, the papayas were stored for 12 days at 16 ± 1 °C, followed by another 2 days at 21 °C, under relative humidity of 50–60%. In total, 125 fruits were used, which were evaluated in terms of mass loss, firmness, soluble solids (°Brix) and degree of ripeness. From the 14th day on, the control treatment showed the highest mass losses (22.29 ± 3.87%), while QG and QG/Li-lat revealed the lowest values (17.66 ± 2.68% and 17.46 ± 3.68%, respectively), evidencing the action of the coating as a barrier to dehydration. Regarding firmness, the coated fruits maintained values higher than the control since the 8th day. On the 15th day, the control showed only 4.8 ± 1.3N while QG/Gli reached 16.4 ± 5.3N, indicating that the coatings delayed the loss of texture and the softening characteristic of ripening. The soluble solids content increased between the 1st and 8th day in all treatments, except for QG/Gli