Yeast selection as a tool for reducing key oxidation notes in organic wines

- Yeast selection was used as a tool for reducing wine oxidation notes.
- It was based on a high consumption of amino acid acids precursors of oxidation notes.
- Chemical and sensory analyses were performed after an aging process.
- Wines elaborated with selected yeasts led to less “evolved” wines.

The selection of yeasts with certain biotechnology properties has recently emerged as a possible alternative for improving and ensuring wine quality. The aim of this work was to apply yeast selection to the elaboration of organic wines in order to reduce the occurrence of oxidation notes linked to the limitation in the levels of SO2 allowed in its elaboration. For this purpose, controlled fermentations were carried out on natural must with five autochthonous Saccharomyces cerevisiae strains from the Origin Appellation “Vinos de Madrid”. These strains were selected on the basis of their high consumption of amino acid precursors of oxidation notes, such as phenylalanine, methionine and leucine. Chemical and sensory analyses of the samples were performed after the alcoholic fermentation and at months 1 and 3 of an ageing process. Selected yeasts led to less “evolved” wines with lower amounts of aldehydes, such as 2-methylpropanal, 2-methylbutanal, 3-methylbutanal and phenylacetaldehyde and lower scores for most oxidation related aroma descriptors. In particular, wines elaborated with strain CLI 271 had the lowest scores for: “very ripe fruit-raisin-overripe fruit”, “cognac-brandy-sherry wine”, “old wine-matured wine-evolved wine”, “varnish-paint-glue-resin-rubber-solvent”, “honey-molasses” and “liquorice-curry” oxidation notes.