UNRAVELLING THE ROLE OF LACTIC ACID BACTERIA ON SPARKLING WINE ELABORATION THROUGH METABOLOMICS APPROACH

Abstract

Xinomavro is a red grape variety from Northern Greece (Protected Designation of Origin), known for the nice acidities, perfectly appropriate for sparkling wine production (Rosé and Blanc de Noir). The elaboration of sparkling wine requires technical as well as scientific skills. Although the impact of the yeast strains and their metabolites on the final product quality is well documented, the action of bacteria still remains unknown.

The present work focuses (i) on the population diversity of lactic acid bacteria isolated from sparkling wines and (ii) on the technological effect of the species during sparkling wine elaboration. Bacterial strains were typed by multiple loci VNTR analysis (MLVA) based on five tandem repeats loci and 3 different strains were chosen as starters for the sparkling wine production.

Xinomavro base wine was treated according to the winery production protocol and second fermentation was realised in the bottle under 6 different inoculation schemes.1) addition of S. cerevisiae (Lalvin DV10) 2) addition of S. cerevisiae (Lalvin DV10) and Lysozyme (40g/hL) 3) addition of S. cerevisiae (Lalvin DV10) and O. oeni Greek strain (UNIWA collection) 4) addition of S. cerevisiae (Lalvin DV10) and O. oeni French strain (CRBO collection) 5) addition of S. cerevisiae (Lalvin DV10) and O. oeni Commercial strain 6) addition of Schizo saccharomyces pombe strain (NRRL collection). Twelve months after the second fermentation in the bottle, oenological parameters were determined according to the OIV protocols, the volatile compounds produced were measured by GC/MS, and the metabolomic fingerprint analysis were acquired by an UPLC-HDMS-QTof-MS instrument. Finally, all produced wines were evaluated by quantitative descriptive sensorial analysis.

Malolactic fermentations were realized in all cases except the condition n°2 where lysozyme was added. Forty compounds were quantified and separated according to their chemical classes (monoterpenes, norisoprenoids, aldehydes, alcohols, esters, acids, and ketones) while statistical analysis showed the presence of three groups of sparkling wines according to the inoculation scheme. The untargeted metabolomic approach clearly discriminated the action of bacteria and revealed intra species variability at strain level. This is the first time that highlights the role of lactic acid bacteria and precisely of the species of O. oeni to sparkling wine elaboration.