The taste of cooked rice is affected by the gelatinizing characteristic of endosperm starch, which is said to be largely dependant on uneven water absorption of the endosperm. However, this is not clearly shown in the existing researches. Thus, this study observed the water penetration into milled rice in micro structural point of view. The result showed that the water penetrated more deeply on the ventral side compared to the dorsal side, which corresponds well with the distributive characteristics of a hydrophobic protein body (PB-I). On the dorsal side, it was found that water did not penetrate into the single starch granules inside the starch compounds, and also into some portion along the endosperm cell walls. Furthermore, the milled rice in which water turbidity was higher, most of the suspended starch granules in the water became separated from the milled rice as single granules, and water was absorbed well from the single granules of the most outer layers of the milled rice.
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