Aging spectral markers of tequila observed by Raman spectroscopy

摘要： In this work, were studied the aging spectral markers of three types of tequila: Blanco, Reposado, and A?ejo (white, rested, and aged, respectively) by Raman spectroscopy with the aim of qualitatively assessing the aging state of tequilas. The samples were elaborated in the same distillery to increase the correctness of the analysis since the contribution of manufacturing process factors, e.g., the type of water used for the elaboration, the origin of raw materials like agaves, sugar, barrels, and others would be similar for all the kinds of tequila. It was demonstrated that complementary information can be obtained through the employment of two excitation wavelengths: 532 and 785 nm. Fluorescence intensity increases with the aging degree of the tequilas as observed with the 532 nm line providing qualitative information about the resting time within the barrels. Additionally, by employing the 785 nm line it was possible to discern through the νs-CCO νa-CCO bands, (C–O) and (C–H) stretching modes and CH2 wagging bonds, the aging spectral markers of tequila.