When the cooked rice is refrigerated, the starch molecules gradually undergo a reformation process called retrogradation. In food chemistry, retrogradation refers to the phenomenon in which starch returns or reverts to a crystalline structure as it cools down. The result of retrogradation is the formation of resistant starch. This is the same reason why bread in the refrigerator hardens over time.
When bread is stored in the refrigerator, it becomes stale considerably faster than when it is stored at room temperature. This is because the cold temperature of the fridge can speed up the process of starch retrogradation, resulting in a change in the texture of the bread, making it dry and less enjoyable to consume.
Did you ever wonder why bread that’s left over becomes hard and dry, or why rice gets grainy when it’s been in the fridge for a while? Well, it’s because of something interesting called starch retrogradation. This is a natural