Resumen de Ultraviolet spectroscopy study of phenolic substances and other major compounds in red wines: relationship between astringency and the concentration of phenolic substances

J. C. Boulet, Marie-Agnès Ducasse, Véronique Cheynier

• Background and Aim In a previous study, based on statistical considerations, absorbance values at 230 nm provided a good prediction of wine astringency. The present paper seeks spectroscopic arguments to support such a prediction.

  Methods and Results Ultraviolet spectra were acquired for several families of phenolic substances, and for the main wine compounds. Wine absorbance at 230 nm is mainly because of tannins which are the major compounds responsible for astringency in wines.

  Conclusion A good relationship was observed between astringency threshold and absorbance at 230 nm for most of the compounds analysed, confirming the previous results. Moreover, absorbance at 230 nm appeared to balance better the contributions of the different phenolic substances than absorbance at 280 nm.

  Significance of the Study The spectroscopic observations are in agreement with the statistical considerations. Both studies confirm the value of the absorbance at 230 nm for characterisation of red wine phenolic substances and astringency evaluation.