Wax coating and Ag-TiO2 nanoparticles as alternatives to preserve postharvest quality of the purple passion fruit (Passiflora edulis f. edulis)

The purple passion fruit (Passiflora edulis f. edulis) is a highly sought climacteric fruit on the global market, but its short postharvest life makes international commercialization difficult. The objective of this study was to evaluate the implementation of wax coatings and silver-doped titanium dioxide nanoparticles (Ag-TiO2-NPs) to preserve the postharvest quality parameters of the purple passion fruits. After the waxes and NPs synthesized using the combustion solution method were applied, the fruits were packed in plastic bags and cardboard boxes. Treatments were evaluated under two different storage conditions: room temperature (18°C, domestic market) and refrigeration (7°C, export market) during 1 week of shelf life. Physicochemical variables were measured periodically, and at the end of each storage condition, a consumer perception analysis was performed using natural language processing. The coating treatments did not favor postharvest behavior in the two experiments, and only increased brightness of the fruits was evident. In the refrigeration experiment, the application of Ag-TiO2-NP alone had a positive effect on the delaying parameters like respiration rate (decrease of up to 55% compared to the control), color (up to 80% less), total soluble solids (lower by ∼ 10%), and titratable acidity (increased ∼ 5%), with no effect on the perception of taste and visual characteristics identified by consumers. However, this treatment did not show consistent effects at room temperature (18°C). These findings support the viability of nanoparticle application as a strategy to preserve the postharvest quality of passion fruit destined for exportation and wax coatings to improve visual fruit perception.