A new approach for sensory characterization of grapes: relationship with chemical composition

This study, part of the Doctoral Thesis of Sara Ferrero, is a joint collaboration between ICVV (Logroño - Spain), the University of Zaragoza (Spain) and the Fondazione Edmund Mach (Italy). The aim was to characterize taste and mouthfeel properties of grapes elicited by the phenolic fraction (PF) of grape berries and establish relationships with chemical variables.

María Pilar Saenz-Navajas explain that as many as 31 diverse grape lots of Tempranillo Tinto and Garnacha Tinta from three different regions were harvested. Grapes were destemmed and macerated in 15% of ethanol for one week and extracts were submitted to solid phase extraction. The recovered polyphenolic fraction was reconstituted in wine model and characterized by a panel of 21 wine experts employing a list of 23 taste and mouthfeel-related attributes following a rate-k-attributes methodology.

Six significant attributes among the 31 samples differed based on ANOVA results, and three main independent dimensions defining the sensory space of PFs were identified, but which were they? Could be satisfactory modeled by PLS-regression from chemical parameters? Did tannin activity and tannin concentration along with mDP of tannins prove to be good predictors of perceived dryness? Which prediction power do flavonols have? Which molecules were involved in the formation of the "dry" "sticky" and "sticky/bitter" attributes?  dimension?

Find out why this study has increased our knowledge about some of the chemical drivers of grape sensory properties and presents a powerful tool for the wine industry to assess grape quality.

Video of the seminar held during Macrowine virtual (June 23-30, 2021)

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