Raman spectroscopy of white wines

• Laser induced fluorescence of white wines with 325 nm excitation is assigned to hydroxycinnamic acid derivatives.
• Evidence of selective enhanced resonance Raman scattering with 325 nm excitation of hydroxycinnamic acids.
• Glucose and fructose content may be determined by means of Raman spectroscopy.

The feasibility of exploiting Raman scattering to analyze white wines has been investigated using 3 different wavelengths of the incoming laser radiation in the near-UV (325 nm), visible (532 nm) and near infrared (785 nm). To help in the interpretation of the Raman spectra, the absorption properties in the UV–visible range of two wine samples as well as their laser induced fluorescence have also been investigated. Thanks to the strong intensity enhancement of the Raman scattered light due to electronic resonance with 325 nm laser excitation, hydroxycinnamic acids may be detected and analyzed selectively. Fructose and glucose may also be easily detected below ca. 1000 cm−1. This feasibility study demonstrates the potential of the Raman spectroscopic technique for the analysis of white wines.