Faculty of Life and Environmental Sciences, University of Tsukuba, 1-1-1 Tennodai, Tsukuba, Ibaraki 305-8572, Japan.
School of Science and Technology, Kwansei Gakuin University, 2-1 Gakuen, Sanda, Hyogo 669-1337, Japan.
Food Chem. 2018 Aug 30;258:308-313. doi: 10.1016/j.foodchem.2018.03.089. Epub 2018 Mar 21.
The difference in Raman spectra for different excitation wavelengths (532 nm, 785 nm, and 1064 nm) was investigated to identify an appropriate wavelength for the quantitative analysis of carotenoids in tomatoes. For the 532 nm-excited Raman spectra, the intensity of the peak assigned to the carotenoid has no correlation with carotenoid concentration, and the peak shift reflects carotenoid composition changing from lycopene to β-carotene and lutein. Thus, 532 nm-excited Raman spectra are useful for the qualitative analysis of carotenoids. For the 785 nm- and 1064 nm-excited Raman spectra, the peak intensity of the carotenoid showed good correlation with carotenoid concentration; thus, regression models for carotenoid concentration were developed using these Raman spectra and partial least squares regression. A regression model designed using the 785 nm-excited Raman spectra showed a better result than the 532 nm- and 1064 nm-excited Raman spectra. Therefore, it can be concluded that 785 nm is the most suitable excitation wavelength for the quantitative analysis of carotenoid concentration in tomatoes.
研究了不同激发波长（532nm、785nm 和 1064nm）的拉曼光谱差异，以确定用于定量分析番茄中类胡萝卜素的合适波长。对于 532nm 激发的拉曼光谱，分配给类胡萝卜素的峰的强度与类胡萝卜素浓度没有相关性，而峰位移反映了类胡萝卜素组成从番茄红素向β-胡萝卜素和叶黄素的变化。因此，532nm 激发的拉曼光谱可用于类胡萝卜素的定性分析。对于 785nm 和 1064nm 激发的拉曼光谱，类胡萝卜素的峰强度与类胡萝卜素浓度呈良好相关性；因此，使用这些拉曼光谱和偏最小二乘回归建立了类胡萝卜素浓度的回归模型。使用 785nm 激发的拉曼光谱设计的回归模型的结果优于 532nm 和 1064nm 激发的拉曼光谱。因此，可以得出结论，785nm 是定量分析番茄中类胡萝卜素浓度的最适激发波长。
