NEW PLANT BIOPOLYMERS FOR THE COLLOIDAL STABILITY OF THE COLORING MATTER OF RED WINES
The color as well as the “clarity” of red wines are ones of the qualities required by the consumers. Red wines must have colloidal stability from its bottling to its consumption. The supplementation of red wines with additives, and especially Acacia senegal gum, contributes to its organoleptic properties such as the colloidal stabilization of the coloring matter. In a global perspective of limitation of additives in the field of enology, one of the objectives is notably (i) to reduce the use of additives in wines, by their num- ber and/or their quantity, and (ii) to favor the use of natural additives while preserving the organoleptic and sensory qualities of wines.
The aim of this work is to identify some plant biopolymers, other than Acacia senegal gum, allowing the colloidal stability of the coloring matter of red wines, and satisfying the technical (solubility and non-clogging) and sensory requirements of wine making. The selected plant biopolymers should also significantly improve the coloring matter colloidal stability.
Nine natural different plant biopolymers were used in this study. Their biochemical composition (protein and carbohydrate contents, amino acids and sugar compositions) and structural properties (Molar mass, polydispersity and intrinsic viscosity) were characterized. The colloidal stability proper- ties of all biopolymers were evaluated in comparison to Acacia senegal gum on three different matrices: a mineral-hydro-alcoholic solution corresponding to the test recommended by the oenological codex (COEI-1-GOMARA:2000), a hydro-alcoholic-grape marc solution, and unstable red wines.
The use of nine natural different plant biopolymers allowed to identify their intrinsic biochemical and structural properties essential for the colloidal stability of the coloring mater. Among these nine plant biopolymers, one of them presents interesting colloidal stabilization properties towards the coloring matter. This plant biopolymer possesses superior colloidal stability properties than Acacia senegal gum and good clogging index. Its quantity in red wines can be reduced between 5 and 10 while maintaining the colloidal stability of the coloring matter and allowing the filtration of red wines. This increased effi- ciency towards the colloidal stability of the coloring is correlated to the intrinsic biochemical and struc- tural properties of this exudate. This natural exudate could therefore be of interest for its use in enology.
Issue: OENO Macrowine 2023
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Plant exudate, Coloring matter, Colloidal stability