Yeast influence on the formation of stable pigments in red winemaking.

The anthocyanin profile of a wine greatly varies over time depending on many factors. In addition to color modifications due to changes in the chemical composition of wine, there may be some influence of the yeast strain used in fermentation. The main aim of this study is to identify and quantify the different ways in which yeast may influence on wine color and its stability, during red winemaking. Hydroxycinnamate decarboxylase activity was measured by the ability to transform the p-coumaric acid (HPLC-DAD). Acetaldehyde (GC-FID) and pyruvic acid (Y15 enzymatic autoanalyser) contents were monitored along fermentation. Stable pigments formation, including vitisins, vinylphenolic pyranoanthocyanins and flavanols-anthocyanins adducts, were analyzed by HPLC-DAD/ESI-MS. Moreover, the ability of adsorbing color molecules by yeasts' cell walls was assessed. It could be concluded that the strain used has substantial influence on the formation of stable pigments, and therefore, proper yeast selection is important to ensure the stability of the wine coloring matter.