Effect of Temperature and Moisture Content on Water Diffusion Coefficients in Rice Starch/Water Mixtures

• Published in: Food Science And Technology International (Ibaraki, Japan) Vol. 2; no. 3; pp. 171 - 173
• Main Authors: GOMI, Yuichiro, FUKUOKA, Mika, TAKEUCHI, Shigeki, MIHORI, Tomowo, WATANABE, Hisahiko
• Format: Journal Article
• Language: English
• Published: Japanese Society for Food Science and Technology 1996
• Subjects: diffusion; gelatinization; NMR; rice; starch; temperature dependence; water content
• DOI: 10.3136/fsti9596t9798.2.171
• ISSN: 1341-7592

For simulating the process of cooking rice grains or rice starch-related foods, the knowledge of the water diffusion coefficient as a function of temperature and moisture content is essential. Unfortunately, however, little reliable published data are available. In this paper, the water diffusion coefficient (WDC) in rice starch/water mixture with a selected moisture content was measured by PFG-NMR over a range of temperature. The WDC in a heated sample (0.42-0.89 g H2O/g sample), which was prepared by heating at 90°C for 60 min and cooling in advance, was measured over the temperature range 20-78°C, and that in a non-heated sample (0.465-0.55 g H2O/g sample) was measured at 16-53°C. The correlations between WDC and temperature as well as between WDC and moisture content were examined, and some empirical equations were developed with which the estimation of the WDC at an arbitrary combination of temperature and moisture content was enabled.