To begin with, what is aged rice and new rice? Well, aged rice or old rice is nothing but stocked rice which is kept for ageing for one or more years. On the other hand, new rice is the one which is produced from newly harvested crops.
Now, how is rice aged?
Ageing of rice is perhaps a complicated process in which changes in the physical and chemical properties of rice grain takes place. The newly harvested crops are stored for a few months to bring a change in flavor and texture in it. However, the main components of the rice like starch, protein and lipids remains unchanged during ageing and only structural changes take place along with change in flavors and texture.
The basic difference in the nature of aged rice and new rice that one gets to see while cooking it is that new rice produced from newly harvested crops need less water to be cooked since the newly produced rice stay hydrated unlike aged rice. In case of aged rice, the moisture content is less and it always stays separated and looks good after cooking while new rice tends to become sticky. Aged rice need more water while being cooked in comparison to new rice and ends up fluffy in texture.
It is often suggested by nutritionists that aged rice is a healthier option as compared to new rice due to the change in pasting properties that occur during ageing.