黑米原花青素的红外光谱分析

Analysis of black rice procyanidins by fourier transform infrared spectroscopy(FTIR)

原花青素是一种多酚类物质,目前被公认为清除人体中自由基效果最好的天然抗氧化剂。为充分利用这一资源,以黑米为研究对象进行原花青素提取与纯化,通过超微粉碎技术并结合有机溶剂丙酮的双水溶性,实现原花青素分子的释放,利用膜过滤与大孔树脂吸附相结合的方法进行原花青素物质的分离纯化,通过红外光谱技术中不同官能团和化学键的吸收峰强度的差异构成波数分布极为清晰的红外光图谱,再结合二阶导数图谱实现黑米原花青素结构解析。结果表明:黑米原花青素纯化前后均于3650～3200 cm^(-1)处有强吸收峰,发生羟基的伸缩振动,在1680～1450 cm^(-1)处有强吸收峰,苯环的骨架振动主要集中1596.60 cm^(-1)附近且只有一个吸收峰,同时,在指纹区域796.46 cm^(-1)处出现苯环上的不饱和C-H面外变形振动吸收峰。此外,黑米原花青素纯化后各峰值强度均变弱。由此可得,黑米原花青素是混合多聚原花青素类,其结构单元主要为原花青定。

Procyanidins is a polyphenolic substance that has been recognized as the best natural antioxidant that can effectively remove free radicals from the human body.In order to make full use of the resources,the study extracted and purified the procyanidins from black rice as research target,changed the geometry of the material particles by the ultra-fine pulverization technology and combined the dual water-solubility of the organic solvent acetone to achieve the release of procyanidins molecules by disruption of hydrogen bonding force between procyanidin and black rice macromolecule proteins and cellulose molecules,separated and purified procyanidins by membrane filtration technology and macroporous resin.Then constituted a very clear infrared spectrogram of wavenumber distribution by differences in intensity of absorption peaks by different functional groups and chemical bonds in infrared spectroscopy,combined with the second derivative atlas to achieve black rice procyanidins structure analysis.The results showed that black rice procyanidins had strong absorption peaks around 3650~3200 cm-1 whatever before and after purification,because the hydroxyl stretching vibration occurred,and the absorption peak appears at 3650~3200 cm-1,the skeleton vibration of the benzene ring mainly concentrates around 1596.60 cm-1 and has only one absorption peak.At the same time,the absorption peak of the unsaturation C-H out-of-plane deformation on the benzene ring occurs at the 796.46 cm-1 fingerprint area.In addition,the peak intensities of the black rice procyanidins were all weak after purification.It can be concluded that black rice procyanidins are mixed poly-procyanidins and their structural units are proanthocyanidins fractions.