Impact of winemaking processes on wine polysaccharides, improving by qNMR

Abstract

AIM: Today the knowledge in terms of molecular composition of the colloidal matrix is ​​not enough in order to control its stability, according to the number of winemaking and wine stabilization processes. The physico-chemical processes during the winemaking change the composition and quantity of wine macromolecules. The goal today is to determine which analytical techniques will allow to discriminate these winemaking processes in order to better understand their impact on colloidal matrix stability as well as which molecules are responsible for its instabilities.

METHODS: Wines obtained after conventional winemaking were subjected to different fining and chemical stabilization treatments. Different methods were used to investigate the wine macromolecular composition and stability after chemical stabilization, including quantitative and qualitative analyzes of total soluble polysaccharides by extraction under acidified ethanol, and by size exclusion separation as well as qNMR metabolomics.

RESULTS: Observation of a slight difference at the quantitative level using classical analysis between the winemaking processes was observed as well as a strong discrimination by qNMR metabolomics.

CONCLUSIONS:

Analyses of total soluble polysaccharide of wine after different treatment shows different types and amount of these molecules. The qNMR metabolomics confirme the discrimination between each treatment. It allows a strong discrimination and is a step towards in the identification of winemaking processes. More investigations still require to determine which are the key parameters involved the wine colloidal stability as well as the right stabilization products, physicochemical winemaking processes, depending on the wine. The qNMR allows to understand, improve and choose the vinifications processes and the physicochemical stabilization of the colloidal matrix of wines, while respecting the quality and typicity of the most Bordeaux wines.