This paper describes the adaptation of a one-dimensional rice cooking model including water transfer,
starch phase transitions and swelling to simulate both milled and brown Chu-cheong and Chil-bo rice cultivars
cooked in excess water or in limited amounts of water. The pericarp was found to play a temperature-dependent
role during steeping of brown rice. At 50 C, surface mass-transfer resistance was
identified whereas from 75 C the pericarp ruptured. Despite pericarp rupturing, apparent water diffusion
coefficients for brown rice (1.9 1010 m2 s1
) were lower than for milled rice (3.3 1010 m2 s1
).
This was due to the mechanical constraining effect of pericarp with respect to water uptake. In the limited-water
cooking mode, predicted water and gelatinization profiles of four selected cooking procedures
explained the texture of cooked rice. Indeed, the highly hydrated gelatinized periphery of the cooked
grain resulted in high ‘‘initial starchy coating’’ sensory scores whereas the uncooked core increased
instrumental firmness.
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