Use of heat treatment and UV-C irradiation to prevent chilling injury and chitosan as coated in Tommy Atkins and Palmer mangoes

Abstract

This work carries out to determinate the temperature vs. time interactions, that they can cause chilling, injury in 'Tommy Atkins' and 'Palmer' mangoes, with evaluation of their metabolism alterations, it is permitting that test the use of heat treatment and UV -C irradiation to minimize or eliminate these damages. Also it will evaluate the chitosan's efficiency as alternative at wax, usually used after the heat treatment. In the first experiment, fruits harvested medium-ripe, they will be stored at 2°C, 5°C and 12°C for 1, 2, 3 and 4 weeks. After each evaluation period, the mangoes will be transferred to ambient temperature for one week. In the second experiment, part of fruits will be treated with heat at 46.1°C for 60 or 90 min and at 55°C for 5 minutes, and the other part will be submitted of UV-C irradiation (energy level of 2.46kJ.m-2) for 5 min and 10 min, before the storage under chilling injury condition indicated in the first experiment. In the third experiment, fruits treated with heat or UV-C irradiation, they will be coated with carnauba wax or with 1% and 2% chitosan solutions, before the storage under chilling injury condition indicated in the first experiment. After this period, the mangoes will be transferred to ambient temperature for 7 days. The fruits will be evaluated weekly during the refrigerated period, and each two days after they transferred to the ambient condition, for appearance, coloration, incidence of decay, weight loss, firmness, chilling damages, respiratory activity, solid soluble, titratable acid, soluble and reducing sugars, ascorbic acid and total polyphenols contents, total antioxidant activity and peroxidase, polyphenoloxidase and phenylalanine ammonia-lyase enzymes. (AU)