Nakagawa Kouichi, Maeda Hayato
Division of Regional Innovation, Graduate School of Health Sciences, Hirosaki University.
Faculty of Agriculture and Life Science, Hirosaki University.
J Oleo Sci. 2017;66(5):543-547. doi: 10.5650/jos.ess16245.
We investigated the location and distribution of paramagnetic species in black and white rice using electron paramagnetic resonance (EPR), X-band (9 GHz) EPR imaging (EPRI), and HPLC. EPR primarily detected two paramagnetic species in black rice, which were identified as a stable radical and Mn species, based on the g values and hyperfine components of the EPR signals. The signal from the stable radical appeared at g ≈ 2.00 and was relatively strong and stable. Subsequent noninvasive two-dimensional (2D) EPRI revealed that this stable radical was primarily located in the pigmented region of black rice, while very few radicals were observed in the rice interior. Pigments extracted from black rice were analyzed using HPLC; the major compound was found to be cyanidin-3-glucoside. EPR and HPLC results indicate that the stable radical was only found within the pigmented region of the rice, and that it could either be cyanidin-3-glucoside, or one of its oxidative decomposition products.
我们使用电子顺磁共振（EPR）、X波段（9吉赫兹）电子顺磁共振成像（EPRI）和高效液相色谱法（HPLC）研究了黑米和白米中顺磁物质的位置和分布。EPR主要在黑米中检测到两种顺磁物质，根据EPR信号的g值和超精细成分，它们被鉴定为一种稳定自由基和锰物质。稳定自由基的信号出现在g≈2.00处，相对较强且稳定。随后的非侵入性二维（2D）EPRI显示，这种稳定自由基主要位于黑米的色素区域，而在米粒内部观察到的自由基很少。使用HPLC分析从黑米中提取的色素；发现主要化合物是花青素-3-葡萄糖苷。EPR和HPLC结果表明，稳定自由基仅在米粒的色素区域内发现，并且它可能是花青素-3-葡萄糖苷或其氧化分解产物之一。
