Effects of Ethylene Absorbent on Polygalacuturonase Activity of Persimmon Fruit

Abstract

The inclusion of an ethylene absorbent in the polyethylene bag is known to be effective in extending the storage period of persimmon. The polygalacturonase (PG) activity in the persimmon fruit placed in polyethylene bags with or without abosrbent was compared during storage at room temperature (about 20°C) and 5°C. PG is considered to decrease the quality and hardness of persimmon fruit during storage by its action on the pectic substances. Therefore, the activity of PG has been used as an index of the quality and hardness of the fruit. The PG activity in the insoluble fraction of persimmon fruit was higher in the presence than in the absence of an ethylene absorbent at room temperature. In contrast, no significant differences were observed in its activity in the soluble fraction. PG activity in the soluble fraction at 5°C tended to be higher than at room temperature in the presence of an ethylene absorbent. Although ethylene absorbent prevents the decomposition of total pectin at room temperature, PG activity was hardly affected by temperature or the presence of ethylene absorbent. It may be concluded that the effect of ethylene absorbent on PG is less significant than that of invertase (10) and that PG is not closely related to the softening of the fruits.