Sensory and chemical characterisation of the aroma of Prieto Picudo rosé wines: The differential role of autochthonous yeast strains on aroma profiles José Manuel Álvarez-Pérez a , Eva Campo b,⇑ , Felipe San-Juan b , Juan José R. Coque a , Vicente Ferreira b , Purificación Hernández-Orte b a Research Institute of Vineyard and Wine, University of León, Ponferrada 24400, Spain b Laboratory for Aroma Analysis and Enology, Aragón Institute of Engineering Research (I3A), Department of Analytical Chemistry, Faculty of Sciences, University of Zaragoza, Zaragoza 50009, Spain article info Article history: Received 26 April 2011 Received in revised form 15 October 2011 Accepted 14 January 2012 Available online 24 January 2012 Keywords: Wine Aroma Yeast Fermentation Sensory analysis GC–O Prieto Picudo abstract This study evaluates the specific impact of isolated yeast strains on the aromatic profile of fermented musts from Prieto Picudo, an autochthonous Castilla y León (Spain) red grape variety with an increasing demand in the local marketplace. For this purpose, the aroma profiles of wines elaborated from Prieto Picudo grapes have been studied by sensory analysis, gas chromatography–olfactometry (GC–O) and gas chromatography–mass spectrometry (GC–MS), with the aim of determining the potential of each strain to generate distinctive varietal and fermentation-derived aromatic compounds. The results have shown that the yeast strain exerts a critical influence on the levels of some fermentative (linear and branched ethyl esters, fatty acids, ethyl phenylacetate) and varietal compounds (4-mercapto-4-methyl- 2-pentanone, 3-mercaptohexylacetate, b-damascenone), thus inducing a deep influence on the final aroma of the wine. Combination of both sensory and chemical data arises as a major tool to monitor the different patterns of aroma release and formation from selected yeast strains during the winemaking process. Ó 2012 Elsevier Ltd. All rights reserved. 1. Introduction The production area of Prieto Picudo, a singular red grape vari- ety of Vitis vinifera, is located in southern León, including a little part of Valladolid (Castilla y León, Spain). Wines produced with this grape variety are commonly designated with the name of the vari- ety, although they are qualified as ‘‘Tierra de León’’, according to the Denomination of Origin (DO), which currently comprises 32 cellars. This DO is currently in full growth due to the fact that the DO distinction was conferred only in 2007, which makes it to be the newest DO in Spain. To the best of our knowledge there are no previous studies about the wines made with Prieto Picudo. Wine production has a very long history in this region, stretch- ing back as far as the 10th century. Monasteries and vineyards were established in the area, mainly as a result of the Pilgrim’s per- egrination to Santiago de Compostela crossing the region, but it was not until the 1980s when the enological industry began to develop. In the 1980s a group of winemakers made the first moves towards putting this region on the map by starting to produce wines using this local red grape. Since then the production of this variety is in sharp increase. The grape production in the 2010 vintage was 3826,050 kg, with a 45% increment compared to the 2000, whereas the number of sold bottles was 1868,597, which represents an increase of 89% in the last 10 years (statistic data from DO ‘‘Tierra de León’’, www.dotierradeleon.es). Spontaneous alcoholic fermentation of grape must is a very complex process carried out by the sequential development of many different yeast species. The diversity and composition of yeast populations can influence to a large extent the chemical com- position of wines, and therefore its final aroma and flavour profile (for a complete review, see Swiegers, Bartowsky, Henschke, and Pretorius (2005)). The use of commercially available dried yeast strains to inoculate grape musts have become a normal practice in order to establish a high initial yeast population able to accom- plish a controlled alcoholic fermentation (Nikolaou, Soufleros, Bouloumpasi, & Tzanetakis, 2006). However, several studies support the hypothesis that the continuous use of commercial yeasts significantly reduces the variability of strains that appear in spontaneous fermentation, even to the point of displacing the autochthonous yeast strains (Beltran et al., 2002; Constanti, Poblet, Arola, Mas, & Guillamon, 1997). Accordingly, a concomitant reduc- tion on the aromatic complexity of aromas present in wines (Pretorius, 2000) is also reported. For that reason the use of autoch- thonous, or local selected strains of Saccharomyces cerevisiae as starters is rather preferable, since these yeast are well acclimated 0308-8146/$ - see front matter Ó 2012 Elsevier Ltd. All rights reserved. doi:10.1016/j.foodchem.2012.01.024 ⇑ Corresponding author. Tel.: +34 976 761000x3512; fax: +34 976 761292. E-mail address: emcampo@unizar.es (E. Campo). Food Chemistry 133 (2012) 284–292 Contents lists available at SciVerse ScienceDirect Food Chemistry journal homepage: www.elsevier.com/locate/foodchem