To provide cooked rice which is less susceptible to aging for a long period of time after boiling, prevented from drying and less susceptible to deterioration in grain separation properties. This cooked rice quality improving agent is characterized by containing an enzymolysis product of guar gum as an active component. By boiling a mixture containing the cooked rice quality improving agent, rice and water, the cooked rice can be edible even if stored, in particular, in a chilling temperature range (0-10 DEG C) for a long period of time (e.g., 12 hours or more), is less likely to cause problems for a container and ingredients even if microwave-heated, and is suppressed from aging and deterioration in grain separation properties.本發明之目的在於提供一種烹煮後,即使經過長時間也不易老化、可抑制乾脆以及鬆散性不易惡化的米飯。本發明藉由烹煮包含:以瓜爾豆膠酵素分解物為有效成分為特徵的米飯之品質改善用劑、米、以及水的混合物,而可得到下述米飯:該米飯特別是在冷藏溫度帶(0~10℃),即使長時間(例如12小時以上)保存時,也可以食用,或者即使進行電磁波加熱時,也不會損及容器料理材料並可抑制老化與鬆散性之惡化。
