Study of varietal wines from the qualified origin denomination Rioja (Spain): analysis of wine colour, polysaccharides, polyphenols and biogenic amines and amino acides 

A great variability in the amount of polysaccharides recovered at the end of fermentations carried out by pure cultures of 89 non-Saccharomyces yeasts was observed. The utilization of the best polysaccharides producers in mixed cultures with S. cerevisiae resulted in considerable increases in the final concentration of polysaccharides and showed a strain dependent effect on glycerol production as compared to pure culture of S. cerevisiae.

PAs are compartmentalised within the grape berry, and differ in their composition and degree of extractability. Within each compartment, the CWM limits PA extraction firstly by its degree of permeability and secondly its ability to complex with PA molecules.

The interaction between mannoproteins and wine phenolic compounds is a subject of great interest as some studies show the possible impact in color stability and an improvement in the sensory characteristics namely the reduction of red wine astringency.

In this study for the first time, eight natural stilbenes (trans-resveratrol, trans-piceid, cis-piceid, trans-astringin, trans-piceatannol, (+)-trans-s-viniferin, pallidol and hopeaphenol) isolated and purified from Vitis vinifera, were simultaneously separated and analysed within 5 mn by ultra high pressure liquid chromatography coupled with photodiode array detection.

The aim of this work was the identification and quantification of polyphenols present in natural precipitate of a Sauvignon wine. Phenol analysis in wine precipitate was based on acid hydrolysis, CG- MS after derivatization, and LC-MS.