Physico-chemical Responses of Mango (Mangifera indica L. cv. Carabao) Fruit toMelatonin Under Chilling Stress

‘Carabao’ mango fruit is highly susceptible to chilling injury (CI) when stored at sub-optimal temperature for extended period. Melatonin (MLT) was reported to ameliorate chilling injury (CI), hence this study aimed to enhance the cold tolerance of ‘Carabao’ mango fruits through MLT treatment. Mature green mango fruits were dipped for 10 min in varying concentrations (0.1, 0.5 and 1.0 mM) of MLT then stored at 7°C for 6 wk followed by poststorage at 24°C. Significant amelioration of CI with MLT was achieved during the 3- week storage at 7°C. Melatonin at 1.0 mM delayed the onset of CI and reduced the incidence of CI symptoms like lenticel spotting, peel discoloration, vascular streaking, pulp cavitation, and flesh browning. MLT however, did not significantly retard the rate of ripening of mangoes during storage at 7°C. Since ripening was not completely retarded during cold storage, total soluble solids (TSS) content increased although TSS of MLT–treated fruit was lower than the control. On the other hand, titratable acidity upon withdrawal from cold storage and at the ripe stage was not affected by MLT treatment. The high visual quality rating was maintained for t3 wk at 7°C in both treated and control fruit.