Analysis of the chemical profile of sparkling wines fermented with autochthonous yeast strains using a non-targeted metabolomic approach.

The Champenoise technique for the production of sparkling wines is based on "in bottle" re­ fermentation carried out by few commercia! strains belonging to the Saccharomyces cerevisiae species. However, the exclusive use of these strains can cause a flattening of the sensoria! profile. In fact, the role of volatile compounds, produced by the yeasts during the fermentative process, is fundamental for sparkling wines produced starting from local grape varieties and, in particular, from those produced in Apulia (Southern Italy), whose economie importance is continually increasing [1]. To the best of our knowledge, only two studies [2, 3], have to date investigated the impact of the autochthonous starter strains on sparkling wine volatiles profile. Furthermore, no information are available on the oenological potential of indigenous grape cv Maresco for the production of typical sparkling wine. This contribution deals with the evaluation of the influence of native selected yeast strains (ITEM deposited in the Microbial Culture Collection of CNR-ISPA) on the chemical profile of sparkling wines through a non-targeted metabolomic approach based on HPLC-HRMS and GC-MS techniques. Saccharomyces cerevisiae DVlO (Lallemand, USA) was used as control sample. The reported results show that: a)yeast strain affects the levels of some fermentative compounds as well as of polysaccharides, organic acids, phenolic acids and lipids; b)the control sample was characterized by high values of gluconic acid that adversely affects wine foamability, while lower concentrations of this molecule were detected in sparkling wines produced by the other strains selected in Apulia region; e) the selected autochthonous yeast strains were able to produce sparkling wines ensuring low volatile acidity (<0.3 g/L), high glycerol content, a good phenolic and acid profile that influences the foam stability and the sensoria! quality (body, bitterness and astringency); d) a map constituting a useful tool to monitor the different patterns of aroma release can be obtained by HPLC-HRMS/GC-MS correlation analysis. This contribution provides information that will help in modulating the quality of regional sparkling wines obtained from minor autochthonous grape varieties by using selected microbial resources.