Characterization of sparkling wine based on polyphenolic profiling by liquid chromatography coupled to mass spectrometry

Abstract

Polyphenols are phytochemicals naturally present in wines that arouse much interest in the scientific community due to their healthy properties. In addition, their role as descriptors of various wine qualities, such as the geographical origin or the grape variety, cannot be underestimated. Here, Pinot Noir and Xarel·lo monovarietal samples belonging to the sparkling wine production process have been studied, corresponding to base wines from a first alcoholic fermentation (plus malolactic in some cases), base wines resulting from tartaric stabilization, and sparkling wines from a second alcoholic fermentation aged for 3 and 7 months. One of the objectives of this paper is to obtain valuable chemical and oenological information by processing a huge amount of data with suitable chemometric methods. High-performance liquid chromatography coupled with ultraviolet spectroscopy and tandem mass spectrometry (HPLC-UV-MS/MS) has been used for the determination of polyphenols in wines and related samples. The method relies on reversed-phase mode and further detection by multiple reaction monitoring. Concentrations of relevant phenolic compounds have been determined, and the resulting compositional data have been used for characterization purposes. Exploratory studies by principal component analysis have shown that samples can be discriminated according to varietal and quality issues. Further classification models have been established to assign unknown samples to their corresponding classes. For this purpose, a sequential classification tree has been designed involving both variety and quality classes, and an excellent classification rate has been achieved.