Rapid qualitative identification and quantitative detection of three common spice extracts based on SERS technology

In the quality control of braised meat products, the content of spice extract in braised soup is often used as one of the important indexes to evaluate its flavor and quality. However, the existing research methods mostly rely on chromatography-mass spectrometry for quantitative analysis, which has some problems such as complex operation, long period, high requirements for equipment and professional technology. To enable rapid detection of spice extracts while reducing analytical costs and improving efficiency, this study took the main extracts of star anise, Sichuan pepper and chili peppers, namely shikimic acid xanthoxylin and capsaicin, as the research objects. By preparing AuNPs as the substrate material, a rapid classification and recognition method for SERS spectra of the three different spice extracts was constructed. The results showed that the Raman signals of three spice extracts could be obviously enhanced by using AuNPs as substrate, with good reproducibility (RSD < 5.5 %). SERE spectrum could clearly distinguish the differences of SERS peaks of shikimic acid, xanthoxylin and capsaicin. Principal component analysis (PCA) and linear discriminant analysis (LDA) further confirmed clear visual classification of the spice extracts. Finally, based on the SERS spectra of different concentrations, the digital quantitative equations of SERS spectra of three spice extracts were constructed. This work provides a theoretical foundation and technical framework for rapid detection of spice extracts based on SERS technology.