Harvest maturity and concentration and exposure time to acetylene influence initiation of ripening in mangos

The effects of acetylene at 0, 0.1, 0.2, 0.4, 0.8, or 1.6 ml.liter-1 and exposures of 4, 8, 12, or 24 hours on ripening initiation in mangos (Mangifera indica L.) harvested at three stages of maturity were investigated. Ripeness was assessed before and after treatment in 'Tommy Atkins', 'Ruby', and 'Amelie' mangos by analysis of texture, peel, and pulp color development, soluble solids concentration, and pH. The initiation of ripening depended on the acetylene concentration, exposure time to acetylene, the physiological maturity of the fruit at harvest, and on the cultivar. Changes that can occur during ripening had different sensitivities to acetylene gas. Acetylene treatment of 0.1 or 0.2 ml.liter-1 for 24 hours at 25C initiated softening, but had no effect on the other ripening processes measured. All the ripening changes measured were initiated with a 24-hour exposure to 0.4 ml.liter-1 in 'Tommy Atkins', while 0.8 ml.liter-1 was required with 'Ruby' mangos. There was an interaction between gas concentration and exposure time taken to initiate ripening. The 0.8 ml.liter-1 acetylene treatment required 24 hours to initiate full ripening, while 8 hours were required with 1.6 ml.liter-1 acetylene and 1.0 ml.liter-1 ethylene. Mature and half-mature fruit showed a similar response to gas treatments; immature fruit failed to show full ripening initiation, although softening and peel color development were enhanced