Macrowine 2021
IVES 9 IVES Conference Series 9 Quantification of red wine phenolics using ultraviolet-visible, near and mid-infrared spectroscopy combined with chemometrics

Quantification of red wine phenolics using ultraviolet-visible, near and mid-infrared spectroscopy combined with chemometrics


The use of multivariate statistics to correlate chemical data to spectral information seems as a valid alternative for the quantification of red wine phenolics. The advantages of these techniques include simplicity and cost effectiveness together with the limited time of analysis required. Although many publications on this subject are nowadays available in the literature most of them only reported feasibility studies. In this study 400 samples from thirteen fermentations including five different cultivars plus 150 wine samples from a varying number of vintages were submitted to spectrophotometric and chromatographic phenolic analysis. Anthocyanins, total phenolics, tannins, colour density and the most representative compounds within the main phenolic families (hydroxicinnamic acids, flavan-3-ols, flavonols and anthocyanins) were quantified. Spectra were recorded in different regions of the electromagnetic spectrum. Particularly the information contained in the ultraviolet-visible region as well as in the near and mid-infrared regions was collected. Regression models were built and validated. The interpretation of the loadings and coefficients of regression, the evaluation and analysis of the correlation among variables and the measured phenolic compounds as well as the chemistry basis behind each quantified compound was extensively investigated and reported. Spectral pre-processing techniques as well as variable selection tools were also investigated and selected based on model performance. Accurate models for most of the phenolic compounds and spectroscopies were obtained with residual predictive deviation (RPD) values higher than 2.5. The results obtained showed UV-visible and infrared spectroscopy as valid approaches for the quantification of the phenolic content throughout the winemaking process. Considerations such as easiness of use and the economical and human resources involved in the analysis will also be discussed.

Publication date: May 17, 2024

Issue: Macrowine 2016

Type: Poster


Jose Luis Aleixandre-Tudo*, Helene Nieuwoudt, Wessel du Toit

*Stellenbosch University

Contact the author


IVES Conference Series | Macrowine | Macrowine 2016


Related articles…

Correlations between sensory characteristics and colloidal content in dry white wines

Must clarification is an important step occurring just after grape extraction in the elaboration of white wine, consisting in a solid-liquid separation. Traditionally, low must turbidity, around 50-150 NTU, is generally reached in white winemaking in order to prevent reductive aromas and facilitating alcoholic fermentation. Alternatively, a higher turbidity (300 NTU or above) can be sought for reasons such as a better expression of grapes identity (terroir), or for getting a must matrix that could supposedly lead to wines having greater ageing potential.

Maturation of Agiorgitiko (Vitis vinifera) red wine on its wine lees: Impact on its phenolic composition

Maturation of wine on lees (often referred as sur lie) is a common practice applied by many winemakers around the world. In the past this method was applied mainly on white and/or sparkling wine production but recently also to red wine production. In our experiment, we matured red wine on wine lees of two origins: a) Light wine lees, collected after the completion of the alcoholic fermentation, b) Heavy lees, collected after the completion of the malolactic fermentation. The lees were free of off-odors and were added in the red wine in percentage 3% and 8%, simulating common winemaking addition. The maturation lasted in total six months and samples were collected for analysis after one, three and six months. During storage the lees were stirred.

Metabolomics comparison of non-Saccharomyces yeasts in Sauvignon blanc and Shiraz

Saccharomyces cerevisiae (SC) is the main driver of alcoholic fermentation however, in wine, non-Saccharomyces species can have a powerful effect on aroma and flavor formation. This study aimed to compare untargeted volatile compound profiles from SPME-GC×GC-TOF-MS of Sauvignon blanc and Shiraz wine inoculated with six different non-Saccharomyces yeasts followed by SC. Torulaspora delbrueckii (TD), Lachancea thermotolerans (LT), Pichia kluyveri (PK) and Metschnikowia pulcherrima (MP) were commercial starter strains, while Candida zemplinina (CZ) and Kazachstania aerobia (KA), were isolated from wine grape environments. Each fermentation produced a distinct chemical profile that was unique for both grape musts. The SC-monoculture and CZ-SC sequential fermentations were the most distinctly different in the Sauvignon blanc while the LT-SC sequential fermentations were the most different from the control in the Shiraz fermentations.

Novel analytical technologies for wine fingerprinting in and beyond the laboratory

For characterization, sensory designing and authentication rapid analytical technologies have become available. Some, like Proton Transfer Reaction Mass Spectrometry allow a rapid spectrum of the volatile compounds of wines. Combined with chemometrics wines can be characterized. The same approach can be used to calculate the results of virtual mixtures and allow formulation of constant quality blends. Other new techniques and portable devices based on spectroscopy allow measurements on production sites and in grocery stores, even for the smart consumer. We will present some examples of the application of these techniques for authentication of wines, both in the laboratory and on site.

Supramolecular approaches to the study of the astringency elicited by wine phenolic compounds

The objective of this study is to review the scientific evidences and to advance into the knowledge of the molecular mechanisms of astringency. Astringency has been described as the drying, roughing and puckering sensation perceived when some food and beverages are tasted (1). The main, but possibly not the only, mechanism for the astringency is the precipitation of salivary proteins (2,3). Between phenolic compounds found in red wines, flavan-3-ols are the group usually related to the development of this sensation. Other compounds, phenolic or not, like anthocyanins, polysaccharides and mannoproteins could act modifying or modulating astringency perception by hindering the interaction between flavanols and salivary proteins either because of their interaction with the flavanols or because of their interaction with the salivary proteins.