Impact of pressure and temperature on the hydration resistance of rice
Journal
LWT
Journal Volume
209
Start Page
116759
ISSN
0023-6438
Date Issued
2024-10
Author(s)
Abstract
Crop soaking, a hydration process driven by diffusion, is essential for applications such as milling and germination. This study investigated the moisture absorption of rice kernels during soaking, considering factors like pressure and temperature. The experimental data were analyzed using the Peleg model to understand hydration kinetics, revealing a strong correlation between empirical and regression data, with determination coefficients mostly exceeding 0.99. The study also assessed soaking hydration resistance, identifying contributions from various rice layers, including the husk and bran. Moisture content increased gradually with soaking time, with higher temperatures enhancing absorption. Under normal pressure, white rice absorbed water faster than paddy and brown rice, with brown rice exhibiting higher hydration resistance. Interestingly, paddy rice soaked faster than brown rice under certain conditions due to the air layer between husk and bran, which was eliminated under vacuum or higher temperatures, though the water replacing the air remained unabsorbed. This study aggregated hydration resistance from each kernel to determine layer resistance and specific diffusivity of husk and bran. • The air layer between husk and bran is a key factor in resisting paddy hydration. • The entire resistance can fragment into individual layer-resistance. • Vacuum boosts rice hydration, reducing soak time. • Soaking at high temperatures enhances the hydrate rates.
Publisher
Elsevier BV
Type
journal article