荔枝蜜拉曼光谱指纹图谱的研究

本文以20批从化荔枝蜜为研究对象,采用显微共焦拉曼光谱技术,在785 nm下建立荔枝蜜的拉曼光谱指纹图谱。荔枝蜜的拉曼光谱在424、521、629、706、820、867、918、1079、1122、1266、1460 cm-1处出现强峰,在452、596、776、918、981、1337 cm-1处出现较明显的拉曼峰,其拉曼谱峰显示出了酰胺类、氨基酸类、蛋白质类、碳水化合物类等的拉曼光谱特征,可以基本判定荔枝蜜中含蛋白质、氨基酸、糖类等物质,这与已知荔枝蜜生化成分基本相符;同时运用Matlab指纹图谱分析软件进行相似度分析,不同批次荔枝蜜相似度在0.97以上,显示出建立的荔枝蜜指纹图谱具有特征性。通过一阶和二阶导数分析,显示出荔枝蜜加工前后在峰形及峰强上有显著变化。研究显示拉曼光谱可以直接、快速鉴别荔枝蜜中的主要成分,其指纹图谱的建立可为蜂蜜的鉴别及在线质量控制提供一定的理论依据。

Fingerprint of the Litchi Honey by Raman Spectroscopic

Laser Raman spectrum technology under 785 nm was used to establish the litchi honey fingerprints. The Roman spectra of litchi honey showed that several characteristic strong peaks were found at 424, 521, 629, 706, 820, 867, 918, 1079, 1122, 1266 and 1460 cm-1. And a few obvious Raman peaks appeared at 452, 596, 776, 918, 981 and 1337 cm-1. The Raman peaks showed spectral features of amide, amino acids, proteins, carbohydrates, etc. It was basically confirmed that litchi honey contained protein, amino acid and carbohydrate, which was basic consistent with the known litchi honey biochemical components. Meanwhile, Matlab fingerprint analysis software was used for similarity analysis, it was demonstrated that the similarity of different batches of litchi honey was no less than 0.97 indicating the litchi honey fingerprint had characteristic. There were significant changes before and after processing litchi honey in peak shapes and peak intensities through analysis of first and second order derivatives. Thus, the main ingredients in litchi honey can be directly identified by Roman spectra and the established fingerprint Raman spectroscopy can provide certain theoretical basis for the identification and quality control of lichi honey.