HYDROTHERMAL TREATMENT IN PREVENTION BROWNING OF LYCHEE PERICARP

Abstract

The browning of litchi pericarp (Litchi chinensis Sonn.) occurs rapidly after harvest, limiting the marketing period of the fruits. The objective of this study was to evaluate the effect of hot water treatments in preventing browning of the pericarp and the maintenance of postharvest quality of litchi fruit. Fruits of litchi cv. Bengal uniformly red pericarp were submitted to immersion in water at tree temperature (45, 50 and 55°C) x five soaking times (0, 4, 8, 12 and 16 minutes) in a completely randomized design with tree replications and five fruit per replicate. After drying, the fruits were packed in polystyrene trays, covered with plastic wrap with 12 mm thick and stored in the lab benches at room temperature (19.0 ± 2.4°C and 75 ± 5% RH) to simulate the exposure conditions at supermarket counters. Every two days, during eight days, were evaluated the weight loss, color of the pericarp, soluble solids, titratable acidity of the pulp and ascorbic acid content of the pericarp and pulp. It was observed that the weight loss was higher in fruits that were not subjected to hydrothermal treatment. Fruits subjected to 50°C during 16 minutes and 55°C in all immersion times were evaluated only until the 4th day, thereafter, these fruits are not suitable for commercialization. Immersion at 45°C during four minutes was the most effective in maintaining the red color of the pericarp and did not affect the quality measured during the experimental period.