卢明倩，黄桂媛，王巧贞，许　超，黄庶识**

(1.广西科学院生物物理实验室，广西南宁　530007；2.广西大学生命科学与技术学院，广西南宁　530004)



温度对β-胡萝卜素二维相关红外光谱的影响*

卢明倩1，黄桂媛1，王巧贞1，许超2，黄庶识1**

(1.广西科学院生物物理实验室，广西南宁530007；2.广西大学生命科学与技术学院，广西南宁530004)

【目的】了解在升温过程中β-胡萝卜素分子内不同基团之间的相互影响。【方法】采用二维相关红外光谱分析技术，研究β-胡萝卜素在30～100℃变温微扰过程中的动态光谱变化。【结果】β-胡萝卜素分子的吸收特征峰在一维红外光谱和二阶导数谱上变化不明显，表明其没有发生氧化反应。二维相关分析表明，反式共轭烯烃C—H面外弯曲振动的968 cm-1，烯烃C—H基团反对称弯曲振动的1 442 cm-1，甲基C—H反对称伸缩振动的2 966 cm-1和烯烃C—H的对称伸缩振动的3 012 cm-1，这些吸收峰的光谱变化对温度比较敏感。同时在微扰过程中，不同基团变化的先后顺序：亚甲基热运动引起的光谱变化快于甲基的，低波数的甲基碳氢对称伸缩振动的光谱变化快于高波数的甲基反对称伸缩振动，烯烃碳氢对称伸缩振动热运动引起的光谱变化快于烯烃碳氢反对称伸缩振动。【结论】在微扰作用下利用二维相关分析可以提高谱图的分辨率，这为β-胡萝卜素在升温过程中构象变化的机理提供实验基础。

β-胡萝卜素温度傅里叶变换红外光谱二维相关分析

Abtract:【Objective】The aim of this study is to analyze the interaction between the different groups of β-carotene in the heating process.【Methods】Two-dimensional correlation spectroscopy was applied to study the dynamic spectral changes of β-carotene from 30℃ to 100℃.【Results】The changes of absorption characteristic peaks of β-carotene were inconspicuous in the conventional FTIR spectra and second derivative FTIR spectra during 30℃ to 100℃,which indicated that they had no oxidation reation.Two-dimensional correlation analysis showed that the changes of absorption peaks at 968 cm-1,1 442 cm-1,2 966 cm-1and 3 012 cm-1were more sensitive to temperature.Meanwhile,the order of different groups changes induced by temperature were as follows:the spectral changes of methylene were faster than methyl,the spectral changes of methyl C-H symmetric stretching vibration in low wavenumber were faster than methyl anti-symmetric stretching vibration in high wavenumber,and olefin hydrocarbon symmetric stretching vibration were prior to olefin hydrocarbon anti-symmetric stretching vibration.【Conclusion】This provides experimental basis for the mechanism of the conformational change of β-carotene in heating process.

0　引言

【研究意义】β-胡萝卜素是类胡萝卜素家族中的一种，其分子结构由单双键相间的长多烯碳原子和位于两侧的β-紫罗酮环组成。……