Asymmetrical Flow Field-Flow Fractionation in the Separation, Characterization and Application of Wine Particle Matter

Wine particle matter is mainly constituted by wine colloids and wine macromolecules. These wine colloidal and macromolecular compounds are barely studied, possibly due to the difficulty in facing the challenges that their study merits. These compounds are mainly formed by polyphenols, proteins and polysaccharides that come from the grape seeds, skins and pulp and even, to a lesser extent, from the winemaking itself, since many of them are released during the process.
These compounds exhibit fundamental properties in relation to the stability of the wine (color, polymerization, haze formation and precipitation) with impact in sensory properties i.e., bitterness, astringency and lastly towards the final quality of the product.
However, there is a lack of understanding of the dynamics of the properties of these compounds during distinct stages of the winemaking process and during storage. This could possibly be due to the lack of methodologies that allow the separation and characterization of these colloidal and macromolecular compounds and their properties at their native state.
These compounds, especially the phenols that are the major part of the colloidal fraction, are highly reactive and tend to undergo changes. Hence, it is of vital importance to develop methodologies for the characterization of these compounds and their properties, and therefore generate a useful knowledge of the dynamics in which these compounds are involved.
This thesis presents a methodology for the separation and characterization of these colloidal and macromolecular compounds using Asymmetrical flow field fractionation coupled with multiple detectors (AF4-UV-MALS-dRI) determining the main macromolecular properties, such as molar mass (MW), hydrodynamic radius (rH), apparent density (ρ ̂), concentration (c) and specific absorptivity (ε) in relation to the processes that occur during vinification.
The understanding and monitoring of these properties along with the effects and changes that occur at colloidal and macromolecular level during the production process chain may enable the control and monitoring of these compounds. In addition, knowledge of their different properties will assist decision making in the manufacturing of wine with a desired profile.