# Bottle Aging Affected Aromatic and Phenolic Wine Composition More than Yeast Starter Strains
###### Abstract  
Volatile and phenolic compounds play a key role in the sensory properties of wine, especially aroma and color. During fermentation, yeasts produce enzymes that affect the skin's phenolic compounds extraction and synthesize some of the most important wine volatile compounds. Generally, selected yeasts of the _Saccharomyces cerevisiae_ (Sc) strains are inoculated, which are responsible for carrying out the wine fermentation, enhancing and highlighting its sensory characteristics and contributing to help achieve the wine typicity, according to the winemaker's criteria. After fermentation, all wines require aging in a bottle to modulate their composition and stability over time. Thus, four different Sc strains (Sc1-Sc4) were inoculated into tanks with Tempranillo grapes to carry out, in duplicate, their fermentation and subsequent aging in bottles (9 months), comparing the aromatic and phenolic composition between them. Results showed differences in the fermentation process (kinetic, ethanol yield), CI, TPI and content of alcohols, esters, anthocyanins, flavonoids and flavanols in wines from the different Sc strains studied. Moreover, in the content in wines of most groups of aromas and phenols, except for total acetate esters and flavonols, aging in a bottle had more influence than the yeast strain used for fermentation. volatile compounds; phenolic compounds; yeasts strain; _Saccharomyces cerevisiae_; wine aging alcoholic fermentation; maloactic fermentation; bottling; Tempranillo; color; aroma +
Footnote †: journal: Applied  
release through fermentation, which determine the physiology and ecology of yeast during fermentation [4]. Thus, in enology, the use of selected yeast strains as active dry yeast is a widespread practice, preferably those yeast starters conditioned for fermentation grape varieties and conditions, wine style and characteristics that allow winemakers to develop and differentiate their products. During fermentation, microorganisms and, particularly, _S. cerevisiae_ catalyze the transformation of some grape primary aroma precursors and release various volatile compounds that constitute the secondary aroma [4]. Thus, yeast synthesizes the aromatic compounds that are quantitatively the most important for the aroma of wine, i.e., esters, higher alcohols, and acids, and qualitatively, in the case of esters [5; 6; 7]. In addition, although grapes are the main source of phenolic compounds, key compounds for the sensory properties of wines and linked to their positive properties for human health [8], the yeast strain that conducts the fermentation can also influence its composition, since the enzymes produced by the yeast affect the phenolic compounds extraction from the grape skins [9]. Further, some metabolites produced by yeasts, such as pyruvate acid and acetaldehyde, are involved in the polymerization reactions between phenolic compounds [10; 11]. The importance of yeast strain in the wine composition and its sensory properties is, therefore, evident. Despite their relative genetic proximity, the wide metabolic diversity among wine _S. cerevisiae_ strains makes their contribution to wine quality different and specific for each one, which explains the great number of strains on the market [4; 12; 13]. On the other hand, once the wine has been elaborated, it is bottled, and this stage is quite important in the wine life, since the wine quality and its properties, when it is consumed, depend on it. Thus, during storage, in general, phenolic compounds and, in particular, anthocyanins, flavonoids, and phenolic acids play a key role in the stabilization of the red wine color [14]. During the wine bottle aging, the volatile and phenolic compounds gradually suffer modifications, mainly due to reactions of oxidation, hydrolysis, esterification, polymerization, etc. [15; 16].