Stony hard (SH) peaches lack the ability to synthesize ethylene during fruit maturation which imparts a crisp flesh even after harvest. However, they can be made to soften and lose their crispness by being subjected to a continuous ethylene treatment. Ethylene treatment at approximately 10ppm for 2～3 days is necessary for SH peach softening. Under experimental conditions, fruit are exposed to a continuous flow of ethylene in order to avoid CO2 damage - a method whose associated costs makes it impractical for commercial use. This study aimed at developing a simple technique to soften SH peach fruit so as to have a desirable texture for eating. We found that SH peaches could be successfully softened by a 3-day treatment regardless of temperature (15, 25, or 30℃) using an improved ethylene emitter and a cardboard box having low gas permeability. The concentrations of O2 and CO2 in the box were kept above 18.3% and below 2.2%, respectively, during the treatment. No gas injuries were observed in the flesh. In fruit samples stored for 2 weeks at 10 or 15℃ prior to treatment, firmness decreased by the same treatment for 2 days, but the texture was worse than that of the fruit treated on the day of harvest. This study indicates that the firmness of SH peach fruit can be easily reduced using an improved ethylene emitter and a cardboard box with low gas permeability, which is cost effective for commercial applications.
