Non-Saccharomyces yeasts, particularly Metschnikowia pulcherrima, are considered alternatives to SO₂ in winemaking, combating specific microorganisms. The sensory profile of the wine is contingent upon the type of yeast, the fermentation conditions, and the concentration and mode of application with Saccharomyces cerevisiae strains (whether pure or used in mixed/sequential co-fermentation). This study assessed the aroma in red wines produced with S. cerevisiae (Sc) and M. pulcherrima (Mp, non-Sc), incorporating variations in the method of addition and the inclusion or exclusion of SO₂. The enological parameters of the wines were slightly affected. Volatile compounds were analysed in the wines through gas chromatography–mass spectrometry (GC-MS) at three moments: at the end of malolactic fermentation (MLF) and after 6 and 9 months of bottle ageing. Sequential fermentation of Sc and Mp reduced the concentration of most identified alcohols and acids, which is favourable, as these compounds can yield undesirable aromas at high concentrations. Regardless of the yeast mixture and Mp dose, a majority of the acetate esters and ethyl esters were quantified at concentrations above their perception thresholds, thus enhancing the sensory quality of the wines. Sensory analysis of wines showed generally positive evaluations. Using non-Saccharomyces as an alternative to SO₂ improves the aromatic profile of wines.

The aim of this work was to analyze and compare the concentration of higher alcohols, esters, and acids in wines from Tempranillo and Tempranillo Blanco. Tempranillo Blanco is a new and little-studied white variety that originated from Tempranillo by a natural mutation. During three seasons, grapevines of both varieties were harvested, and nine wines were made from each. The volatile composition of the wines was determined by GC-MS. In the wines of both varieties, the content of higher alcohols was higher than those of esters and acids. Wines from Tempranillo Blanco had lower content of 2-phenylethanol, methionol, 1-hexanol, benzyl alcohol, and total higher alcohols, but higher hexyl acetate and ethyl decanoate than Tempranillo wines. Total ethyl esters and total esters were higher in Tempranillo wines due to the higher ethyl lactate and ethyl succinate content derivate from the malolactic fermentation that was not made in Tempranillo Blanco. The content of hexanoic and octanoic acids and total acids was also higher in Tempranillo Blanco wines than in Tempranillo. This is one of the first studies carried out on the wine volatile composition of Tempranillo Blanco and therefore contributes to a better understanding of the oenological characteristics of this white variety.

Viticulture faces increasing challenges due to the susceptibility of Vitis vinifera L. to biotic and abiotic stresses, which trigger defense responses involving the synthesis of secondary metabolites. Untargeted metabolomics has become a powerful tool to explore these metabolic changes; however, the efficiency and reproducibility of metabolomic studies strongly depend on the extraction protocol used. Current literature shows variability in sample handling, solvent composition, and extraction conditions. This study aimed to optimize an extraction protocol for secondary metabolites in grapevine leaves to ensure high recovery of compounds relevant to untargeted metabolomics. Leaves of Vitis vinifera L. cv. Tempranillo were collected, pooled, frozen, and ground under liquid nitrogen. A factorial design was used to evaluate the effects of sample mass, sample-to-solvent ratio, and solvent type on extraction efficiency. Extracts were analyzed using UHPLC-QTOF-MS in both positive and negative ionization modes, and multivariate statistical tools (PCA and OPLS-DA) were used to identify discriminant metabolites. Optimal extraction was achieved using 750 mg of leaf powder, a sample-to-solvent ratio of 100 mg/Ml, and methanol 80% acidified with 0.1% of formic acid. This protocol maximizes the recovery of metabolites and provides a robust basis for future untargeted metabolomics studies of grapevine responses.