Faculty of Food and Agricultural Sciences, Fukushima University, Fukushima, Japan.
Graduate School of Agricultural Science, Tohoku University, Sendai, Miyagi, Japan.
Biosci Biotechnol Biochem. 2021 Apr 24;85(5):1056-1062. doi: 10.1093/bbb/zbab003.
This study evaluated the influence of the milling process on solid state of rice flours according to water activity using ATR-FTIR. A band at 1740 cm-1 attributed to the C=O stretching of lipids was detected for crystalline samples, and it disappeared at a high aw range. The CH band at 2930 cm-1 of crystalline samples gradually shifted to a higher wavenumber with aw. This band of the α-formed and wet-milled samples shifted to higher wavenumbers above 0.8aw. A band due to OH stretching mode in the 3500-3000 cm-1 region did not shift with aw. The result obtained from IR spectra suggests that the parameter K calculated by Guggenheim-Anderson-de Boar model reflected not only the interaction between water molecules but also the changes of state in solids. Consequently, the results from this study provide insights about the adsorption properties of nonideal solids such as rice flour.
本研究使用衰减全反射傅里叶变换红外光谱（ATR-FTIR），根据水活度评估了碾磨过程对米粉固体状态的影响。在结晶样品中检测到 1740 cm-1 处归因于脂质 C=O 伸缩的带，在高 aw 范围内它消失了。结晶样品的 2930 cm-1 处的 CH 带随着 aw 的增加逐渐向更高的波数移动。α-形成和湿磨样品的该带在高于 0.8aw 的波数处移向更高的波数。3500-3000 cm-1 区域中归因于 OH 伸缩模式的带没有随 aw 移动。从红外光谱获得的结果表明，Guggenheim-Anderson-de Boar 模型计算的参数 K 不仅反映了水分子之间的相互作用，还反映了固体状态的变化。因此，本研究的结果提供了有关非理想固体（如米粉）吸附特性的深入了解。
