科研之友
微信
新浪微博
Facebook
分享链接
摘要
A three-step infrared (IR) macro-fingerprint method combining conventional IR spectra, and the secondary derivative spectra with two-dimensional infrared correlation spectroscopy (2D-IR), was developed to analyze Spirulina powder before and after gamma irradiation. In the IR spectra, most of the absorption peaks of samples irradiated at 1, 2.7, 6, and 10.4 kGy had lower intensities than the non-irradiated ones, whereas peaks at 1152, 1078, and 1051 cm(-1) were slightly enhanced with irradiation at 2.7, 6, and 10.4 kGy. Their second derivative spectra amplified the differences and revealed that irradiation affected the C=O band of carboxylic acid and esters, and the N-H band of proteins. The peaks at 1746 and 1741 cm(-1), and those at 1730 and 1725 cm(-1) became two broad peaks. Meanwhile, the three sharp peaks at 1548 cm-1, 1544 cm(-1) and 1536 cm(-1) changed to two broad peaks at around 1547 and 1534 cm(-1) after irradiation at doses higher than 1 kGy. The characteristic IR bands from 1700 cm(-1) to 1600 cm(-1), which represent the C=O band in proteins, also have different shapes and intensities after irradiation. The finding indicated that irradiation affected the secondary structures of protein which was confirmed by curve fitting results. During the process of increasing the temperature from 50 to 210 degrees C, the ratio of amide I to II in absorption intensities in the 2D-IR spectra of the irradiated samples varied with different response for different samples. Saccharides in Spirulina powder had a higher thermostability than proteins, but the autopeaks of irradiated samples did show differences from the non-irradiated sample. The intensity of autopeaks at 1012 cm(-1) increased dramatically in the irradiated samples while that of peaks at 1053, 1071, and 1083 cm(-1) decreased after irradiation. Based on the three-step IR macro-fingerprint method, irradiated Spirulina powder samples were successfully and fast identified and discriminated.
- 出版日期2013-4
- 单位中国农业科学院; 清华大学
