Effects of vapor heat treatment (VHT) on peel color, respiration, organic acid, sugar and starch contents of 'Carabao' mangoes

摘要

The maturity of cv. Carabao mango fruits at the time of harvest was determined by specific gravity. Fruits that sank in 1% salt solution (S) were considered fully mature. Fruits that sank in water but floated in the 1% salt solution (Sw), and thosethat floated in water (Fw), were categorized as relatively immature. All fruits were subjected to a hot water treatment (52-55deg C, 10 min) within a day of harvest. Half were then subjected to a vapour heat treatment (VHT) to a pulp temperature of 46deg C for10 min, and the other half served as the untreated control. The fruits were then stored at 25deg C. Sw fruits attained a peel colour index (PCI) of 5 on day 3, whereas S and Fw fruits reached a PCI of 4 on day 4 in the control. VHT had no effect on the rate of peel colour progression; internal breakdown, anthracnose, and stem end rot did not occur in any treatments during the experimental period. Starch content decreased in all fruits during storage; VHT fruits had a lower starch content than the controlimmediately after treatment. Among the sugars in the fruit, sucrose showed the highest concentration. Total sugar and sucrose contents in VHT-fruits were higher than those of the control. Citric acid concentration was highest among the 3 organic acids; it decreased during ripening. VHT effectively reduced citric acid in S or Sw fruits on day 1. Fruit respiration rate was unaffected by VHT.