Effect of the Heating Conditions on Cooked Rice

Relationship between the Physicochemical Properties and Structure of Cooked Rice (Part 2)

Abstract

The results of our preceding examination showed that the degree of hydration of the starch grains in cooked rice was implied in the taste of cooked rice. We further examined the effect of heating conditions during rice cooking on the hydration of starch grains in cooked rice.
A scanning electron microscopic analysis showed that the gelatinization of cooked Koshihikari rice proceeded inversely to the heat supplied during cooking. In cooked rice with full gelatinization, the starch had swollen markedly and gaps between the starch cells were indistinct. On the other hand, cooked Yukihikari rice, regardless of the heating conditions had distinct gaps between the starch cells and the starch had swollen much less. The evaluation of the taste of cooked Yukihikari was lower than that of cooked Koshihikari.
These results indicate that insufficient swelling of starch grains caused by difficult influx of water to starch cells in the endosperm led to an inferior taste of cooked rice.