A new approach for sensory characterization of grape. Relationship with chemical composition

AIM: Characterize taste and mouthfeel properties of grapes elicited by the phenolic fraction (PF) of grape berries and establish relationships with chemical variables. METHODS: 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. RESULTS: Six significant attributes among the 31 samples differed based on ANOVA results: “dry”, “coarse”, “bitter”, “dry on tongue”, “sticky” and “watery”. PCA with VARIMAX algorithm was calculated. Three main independent dimensions defining the sensory space of PFs were identified: D1, “dry on the tongue”; D2, “bitter/ sticky”; and D3: “coarse/dry”. Two out of the three dimensions could be satisfactory modeled by PLS-regression from chemical parameters. Tannin activity and tannin concentration along with mDP of tannins proved to be good predictors of perceived dryness. Flavonols have a good prediction power for “bitter” attribute and the “sticky/bitter” dimension. In addition, the low molecular weight anthocyanins seem to be involved in the formation of the “dry” attribute, whereas large polymeric pigments in the “sticky” attribute and the “sticky/bitter” dimension. CONCLUSIONS: 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.

Authors: Maria-Pilar Saenz-Navajas – Instituto De Ciencias De La Vid Y Del Vino (Ur-Csic-Gr). Department Of Enology, Logroño, La Rioja, Spain,Sara, Ferrero-Del-Teso, Instituto De Ciencias De La Vid Y Del Vino (Ur-Csic-Gr). La Rioja, Spain.  Alejandro, Suárez, Instituto De Ciencias De La Vid Y Del Vino (Ur-Csic-Gr). La Rioja, Spain.  Chelo, Ferreira, Universidad De Zaragoza, Iuma, Spain.  Panagiotis, Arapitsas, Fondazione Edmund Mach, Italy.  Daniele, Perenzoni, Fondazione Edmund Mach, Italy.  Fulvio, Mattivi, Fondazione Edmund Mach, Italy.  Vicente, Ferreira, Universidad De Zaragoza, Ia2, Spain.  Purificación, Fernandez-Zurbano, Instituto De Ciencias De La Vid Y Del Vino (Ur-Csic-Gr). La Rioja, Spain.

Email: mpsaenz@icvv.es

Keywords: pls, phenolic fraction, grape quality, mouthfeel, taste

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