Evaluation of the influence of an active biodegradable coating containing rosemary essential oil on the storage stability of cashew apples

The cashew is a significant crop in Brazil’s Northeast, but its apple is highly perishable. To extend the shelf life of fruits, active edible coatings incorporating essential oils have been explored. This study aimed to develop an active biodegradable coating with rosemary essential oil (REO), applied to cashew apples to evaluate their postharvest quality over 15 days of storage. The control filmogenic solution was prepared by mixing a whey protein solution and a pectin solution at a 4:1 (v/v) ratio, with the addition of a transglutaminase enzyme preparation (8 U/g of whey protein isolate). Two additional solutions were prepared in the same proportions as the control treatment (TC): one with 1% REO (T1) and another with 2% REO (T2). A total of 48 cashew apples were selected, with 2 apples per repetition and two repetitions for each treatment and evaluations on each analysis day: 5, 10, and 15 days of storage. Analyses of reducing sugars, titratable acidity (TA), pH, total soluble solids (TSS), and weight loss were conducted and the means were compared using Tukey’s test (95% confidence). All samples exhibited sugar values around 13 g/Kg (p>0.05) throughout storage. TA and pH showed slight variations, likely due to different maturation stages, with all samples having a TA of 0.13 g/100 g and a pH between 3 and 4 during the storage period (p>0.05). The TSS remained around 10 °Brix in the control throughout the study, while T1 and T2 increased to 11 °Brix by day 15 (p<0.05). Weight loss gradually increased during storage, with reductions around 2 and 3% on day 15 (p>0.05). In conclusion, it cannot be asserted that, under the tested conditions, the coating had a significant impact on the preservation of cashew apples, as all obtained results were comparable to those of the control group.