Hot Water Treatment Maintains Normal Ripening and Cell Wall Metabolism in Mango (Mangifera indica L.) Fruit

'Tainong 1' mango fruit were treated with hot water for 10 minutes at 55 degrees C and then stored at 5 degrees C for 3 weeks. After removal from low-temperature storage, the effects of hot water treatment (HWT) on chilling injury (Cl), ripening and cell wall metabolism during storage (20 degrees C, 5 days) were investigated. HWT reduced the CI development of the fruit as manifested by firmer texture, external browning, and fungal lesions. A more rapid ripening process, as indicated by changes in firmness, respiration rate, and ethylene production, occurred in heated fruit after exposure to low temperature as compared with non-heated fruit. At the same time, the cell wall components in heated fruit contained more water-soluble pectin and less 1,2-cyclohexylenedinitrilotetraactic acid (CDTA)-soluble pectin than those in non-heated fruit. HWT also maintained higher polygalacturonase [enzyme classification (EC) 3.2.1.15] and beta-galactosidase (EC 3.2.1.23) activities as well as lower pectin methylesterase (EC 3.1.1.11) activity. In general, the changes of ripening and cell wall metabolism parameters in the heated fruit after low-temperature storage exhibited a comparable pattern to that of non-cold-stored fruit.