Exploitation of autochthonous yeast potential to enhance the quality of regional wines: the Apulian experience

Apulia is the second Italian wine-producing region and the most important producer of red-rosé wine. One peculiar characteristic of Apulian wines is that the podologic characteristics and the climatic conditions of this region contribute to enrich the wine of aromatic essences and to give, therefore, a characteristic and intense taste to the finished product. The Apulian wine industry is living a moment of great qualitative transformation and the challenge of the market had therefore addressed the productive row towards the use of innovative systems to guarantee and exalt the qualitative characteristics of regional wines. A heartfelt requirement is to being able to pilot and to control the productive activity to obtain wines with peculiar characteristics, with respect of the typicality, that is guaranteed by the denominations of origin. The selection and the employment of new combinations of microorganisms, obtained from the native micro flora would be a powerful instrument to improve the organoleptic and sensory characteristics of the product. Autochthonous yeasts are the micro-organisms better adapted to a specific must, which detain characteristics determined by the variety of the grapes and the terroir and, therefore they are able to exalt the peculiarities (aromas, structure and colour) of a wine. In these last year the research activity of the Institute of Science of Food Production of C.N.R. has been directed to the exploitation of autochthonous microbiota to enhance the quality of regional wines. This research line has been granted by a number of National and Regional Projects and it has been conducted in collaboration between the ISPA and a large number of wine companies. The research activity has generated a virtuous circle, thus allowing the standardization of protocols for wine yeast enological selection and biomass production, the constitution of a Yeast Collection but, most of all, the transfer of technology to a large number of SMEs belonging of the wine production chain. Natural fermentations of Negroamaro, Primitivo and Susumaniello musts have been performed and the Saccharomyces cerevisiae population has been analyzed and characterized by molecular, physiological, enological and technological tests allowing the identification of four indigenous S. cerevisiae strains candidate as autochthonous fermentation starters. The enological properties of the above strains have been evaluated during the vintages 2006-2009, by performing 37 large scale vinification trials in 21 different industrial cellars in Apulia. The obtained results and their implications for the valorisation and the improvement of Apulian typical wines will be discussed.