Nutraceutical coating composition for postharvest conservation of 'Paluma' guava

Abstract

This work assesses the influence of edible coating with nutraceutical properties on post-harvest conservation of guavas 'Paluma'. The experiment comprised of a completely randomized design with four replicates and three fruits per plot. Six treatments were applied combining different concentrations of agar and pomegranate seed oil (PS): T1: 1% agar and 0.1 mL/L PS oil; T2: 2% agar and 0.2 mL L-1 PS oil; T3: 3% agar and 0.3 mL L-1 PS oil; T4: 4% agar and 0.4 mL L-1 oil; T5: 5% agar and 0.5 mL L-1 oil; and T6: control (fruits without coating). After the immersion in treatment solutions, the guavas remained stored in an air-conditioned room for ten days at 10 °C and 40% RH. Fruits without coating (control) ripened faster than coated ones, so the treatments preserved fruit coloration. The treatments T4 and T5 provided the best preservation of peel color, suggesting slower ripening and maintenance of fruit quality, as their colors tended to green and opaque. The firmness of fruits without coating was decreased by 35.15% concerning the coated ones. Treatments T4 and T5 had the lowest loss of fresh mass. On the other hand, T5 showed the lowest soluble solids contents (SS)(13.46%). Titratable acidity (TA), SS/TA ratio, total sugars, and carotenoids were not affected by treatments. The edible coating with 4% of agar plus 0.4 mL L-1 of pomegranate seed oil promoted the best quality traits for the post-harvest preservation of the guavas 'Paluma'.