Colloids are an important component of wines, but their study is challenging due to their instability. Asymmetrical Flow-Field Flow Fractionation (AF4)-multidetection is here proposed as a suitable approach to isolate and characterize red wine colloids in native state. AF4 provided size-separation and enabled quantification of the colloidal content of two wines. The gyration radius of colloids was determined by multi-angle light scattering, and ranged between 25 and 50 nm. Analysis of the collected AF4-fractions showed that proteins, polysaccharides and phenolics were present in different proportions among fractions. The composition of AF4-fractions differed between wines. SDS-PAGE analysis of AF4-fractions indicated the presence of protein-phenolics sub-aggregates only in the fractions containing colloids with small radius. The results allowed proposing a model for red wine colloids structure, which comprises two coexisting entities, one made of covalently linked proteins-phenolics subaggregates interacting by non-covalent forces with polysaccharides, and a second in which only polysaccharides and phenolics are present. The proposed model is consistent with the reported relative stability of red wine proteins, a fact that can be due to the stabilizing activity of polysaccharides. Given that enological practices affect the extraction of proteins, polysaccharides and phenolics, AF4-technique represents a very promising tool to investigate the effects of these practices on wine colloidal aggregation and behavior.

Characterization of red wine native colloids by asymmetrical flow field-flow fractionation with online multidetection

Valentina Marassi
Membro del Collaboration Group
;
Andrea Zattoni
Membro del Collaboration Group
;
Andrea Versari
Membro del Collaboration Group
;
Pierluigi Reschiglian
Membro del Collaboration Group
;
Barbara Roda
Membro del Collaboration Group
;
Andrea Curioni
Membro del Collaboration Group
2021

Abstract

Colloids are an important component of wines, but their study is challenging due to their instability. Asymmetrical Flow-Field Flow Fractionation (AF4)-multidetection is here proposed as a suitable approach to isolate and characterize red wine colloids in native state. AF4 provided size-separation and enabled quantification of the colloidal content of two wines. The gyration radius of colloids was determined by multi-angle light scattering, and ranged between 25 and 50 nm. Analysis of the collected AF4-fractions showed that proteins, polysaccharides and phenolics were present in different proportions among fractions. The composition of AF4-fractions differed between wines. SDS-PAGE analysis of AF4-fractions indicated the presence of protein-phenolics sub-aggregates only in the fractions containing colloids with small radius. The results allowed proposing a model for red wine colloids structure, which comprises two coexisting entities, one made of covalently linked proteins-phenolics subaggregates interacting by non-covalent forces with polysaccharides, and a second in which only polysaccharides and phenolics are present. The proposed model is consistent with the reported relative stability of red wine proteins, a fact that can be due to the stabilizing activity of polysaccharides. Given that enological practices affect the extraction of proteins, polysaccharides and phenolics, AF4-technique represents a very promising tool to investigate the effects of these practices on wine colloidal aggregation and behavior.
Valentina Marassi; Matteo Marangon; Andrea Zattoni; Simone Vincenzi; Andrea Versari; Pierluigi Reschiglian; Barbara Roda; Andrea Curioni
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11585/768816
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