Influencia de las semillas de la uva y de la suplementación con taninos enológicos comerciales sobre el color y la astringencia del vino tinto; aplicación de la resonancia de plasmones superficiales al estudio de las interacciones tanino-mucina

Identificador:  TDX:3395

Handle: https://hdl.handle.net/20.500.11797/TDX3395

Autors:  Gombau Roigé, Jordi

Resum:
Tannins are determinants of the quality of red wine since they exert a great influence on the color, astringency, body, capacity for aging and in general on texture of the wine. Traditionally, tannins come naturally from the berries, being released from seeds and skins during vinification, or from the aging or supplementation with commercial tannins. Chapter 1 of this thesis studies the relationship between berry morphology and color, tannin composition and astringency of red wines of four varieties: Merlot, Cabernet Sauvignon, Tempranillo and Garnacha. The main conclusion of this work was that the seed percentage weight respecto to berry weight weight is the main is a determining factor tannin concentration and the astringency of the wine. In Chapter 2 of this thesis studies the effect as co-pigments of oenological tannins and it is concluded that all oenological tannins studied are very effective as co-pigments. An index is also proposed to measure the effectiveness as copigments of the different commercial tannins. Chapter 3 of this thesis studies the interaction between 3 types of tannins and mucin by means of surface plasmon resonance (SPR). With this aim, the kinetic and thermodynamic constants of the interaction were determined as well as the astringency index of the different tannins. The thermodynamic and kinetic dissociation constants of the tannin-mucin interactions had the highest correlation coefficients with the astringency index. These data suggest that astringency depends not only on the thermodynamic tendency to form the complex between tannins and salivary proteins but also probably on the time required to dissociate the complex.