RESPONSE DIFFERENCES TO HOT AIR TREATMENTS BETWEEN TOLERANT (MANGO) AND SENSITIVE (GUAVA) FRUITS AND THE ROLE OF SUGAR CONTENT AND TREHALASE ACTIVITY

摘要

Heat treatments have several advantages during the postharvest handling of fruits and vegetables, including amelioration of chilling injury, control of decay and insects, and retardation of ripening. Fruits and vegetables show major differences in tolerance to heat. Mangoes are among the tolerant fruits, while guavas are among the sensitive fruits. The objective of this work was to investigate the difference in responses between the 2 fruits and the role of sugar content (glucose, fructose, sucrose, trehalose) and the activity of trehalase in the tolerance/sensitivity to heat. 'Manila' mangoes were heated at 43°C or 48°C and 50% RH for 160 min, and then stored at 10°C and 85% RH for up to 12 days. Guavas were heated at 38°C for 120 min or 43°C for 160 min and then stored at 12°C for up to 12 days. There was no injury in mango, while there was a slight and severe injuries in guava heated at 38°C and 43°C, respectively. Trehalase activity was not detected in mango and increased in guava fruit. There was higher sucrose content in mango than in guava fruit.