Abstract
The effect of MA conditions under high humidity packaging on the occurrence of postharvest Kohansho and the quality attributes of stored 'Kiyomi' tangor (Citrus unshiu Marc. × C. sinensis Osb.) fruit was investigated. Modified atmosphere containing CO2 concentrations less than or equal to 12% and O2 concentrations more than or equal to 10% had no effect on the occurrence of Kohansho under high humidity conditions. However, the occurrence of Kohansho was accelerated when the CO2 level accumulated to 14%. Under the condition that CO2 levels are not too high and O2 levels are not too low, maintenance of a high relative humidity surrounding the fruit is considered to be the main factor for packaging design to prevent Kohansho. Furthermore, excessive CO2 levels (more than 8 %) induced fermentative metabolism, resulting in high ethanol levels. MA conditions had no significant effect on the quality attributes, including firmness, TSS, TA, TSS/TA ratio, and AA contents under the high humidity condition. These qualities were preserved during the storage period, probably resulting from the maintenance of a high relative humidity inside the package. As recommended storage conditions and packaging design guidelines, 'Kiyomi' fruit should be stored particularly under a high relative humidity and should not be exposed to high CO2 levels (>8 %) and /or low O2 levels (<5 %) to prevent Kohansho and preserve high quality.
