3:45 PM - 4:00 PM
[2Cp-04] Potential of magnetic resonance imaging (MRI) to evaluate cooked rice.
Keywords:Magnetic resonance imaging（MRI）, rice, T2 relaxation time, moisture dynamics
We have been collecting data on moisture distribution and dynamics in rice using magnetic resonance imaging (MRI) to evaluate the processing characteristics of rice and to select rice cultivars suitable for specific purposes. In particular, T2 relaxation time and its spatial distribution, which is an indicator of moisture dynamics, are considered to be closely related to the eating quality of rice. In this study, we examined the time-dependent changes in T2 relaxation time in cooked rice during storage to investigate whether the moisture dynamics can be used as an indicator of quality variation during the distribution process. Five cultivars of rice (Koshihikari from Tochigi Prefecture, Koshihikari from Ibaraki Prefecture, Hitomebore from Miyagi Prefecture, Kirara 397 from Hokkaido, and Milky Queen from Nagano Prefecture, all produced in 2023) were used as samples. T2 maps on the day of cooking, the first and third day of storage at 5°C were obtained for each cooked rice sample. The moisture contents of the samples were 60 to 61%, with no significant difference between samples. However, the T2 relaxation time was observed to decrease with increasing storage time. Furthermore, the differences in T2 relaxation time due to cultivar and production area were greater than those resulting from storage. The T2 relaxation time of Koshihikari from Tochigi Prefecture showed a high correlation between taste value and stickiness. These findings indicate that the T2 maps and their time-dependent changes of cooked rice reflect the characteristics of cultivars and their production areas. We are currently studying the effect of the cultivar-specific moisture dynamics on the quality of microwave-reheated cooked rice.