INVESTIGADORES
SANGORRIN marcela paula
congresos y reuniones científicas
Título:
YEAST BIOTA ASSOCIATED WITH TRADITIONAL FERMENTED BEVERAGES IN PATAGONIA
Autor/es:
LOPES, C.A.; SANGORRÍN, M.P; SAEZ, J.; CABALLERO, A.C.
Reunión:
Congreso; YEAST BIOTA ASSOCIATED WITH TRADITIONAL FERMENTED BEVERAGES IN PATAGONIA; 2009
Resumen:
Several raw sources, including cereals and fruits has Wild fruits such as strawberries(Fragaria chiloensis), “maqui” (Aristotelia chilensis), “calafate” (Berberis spp.), apples(Malus sp.), as well as seeds of different plants have been traditionally used byaboriginal communities in Patagonia to prepare different fermented beverages. Aparticularly interesting fermented beverage is that obtained from seeds of the Pehuentree (Araucaria araucana), from which the Mapuche´s communities prepared thefermented beverage called Mudai. No works involving the microbial biota presentduring Mudai and other traditional fermented beverages in Patagonia have beenpublished until now.With the aim of investigate this particular yeast biota for the first time, juices obtainedfrom Pehuen seeds and wild apples obtained in the traditional way were fermented insterile flasks under laboratory conditions (3 fermentations from Pehuen seeds and 2fermentations from apple). Yeast sampling in complete medium was carried out duringthe processes, evidencing maximum population densities of 1.5x108cfu mL-1. Molecularidentification of these colonies by using ITS1-5.8S-ITS2 PCR-RFLP and sequenceanalyses, revealed the presence of only two yeast species at the beginning of Mudaifermentation: Hanseniaspora uvarum and Saccharomyces cerevisiae in percentages of80% and 20% of the total biomass respectively. In Apple fermentations, non-Saccharomyces yeasts corresponded to 25% and 84% of the total isolates at thebegining of the two analyzed fermentations respectively, including isolates belonging toH. uvarum and Metschnikowia pulcherrima. In subsequent stages of all Mudai andapple fermentations, the yeast biota corresponded exclusively to S. cerevisiae in allanalyzed fermentations.Intraspecific analysis of the S. cerevisiae isolates from Mudai fermentations by meansof mtDNA-RFLP analysis evidenced a single restriction pattern. This kind of biologicalhomogeneity is frequently observed in inoculated fermentations in which the yeaststarter selected culture dominate the fermentation process, but it is not expected innatural processes Traditional production of this beverage does not involve the use ofcommercial yeasts; however, the environment in which this product is elaborated is inpermanent contact with commercial yeasts used in bread making. MtDNA-RFLPanalysis of commercial bakery yeasts showed the same molecular pattern detected inMudai fermentations, evidencing a cross-contamination of yeasts in these traditionalfermented products. The intraspecific diversity in S. cerevisiae populations from applefermentation samples are being currently analyzed in order to find indigenousSaccharomyces isolates and to evaluate its phylogenetic relationships with regards towine strains of this species.