Abstract

DUARTE, Filomena L.  and  BALEIRAS-COUTO, Margarida. Evaluation of fermenting grape must yeast dynamics by SSCP profiles. Ciência Téc. Vitiv. [online]. 2012, vol.27, n.2, pp.95-101. ISSN 0254-0223.

Alcoholic fermentation of grape must is a dynamic process involving diverse yeast populations which play an important role in wine characteristics. In order to enable a permanent control by the oenologist rapid and low cost methodologies to identify the species of yeasts present during fermentation should be implemented. Single Strand Conformation Polymorphism technique (SSCP), targeting D1 and D2 domains of 26S rDNA, was tested to differentiate wine yeast species. SSCP profiles were produced for 17 collection strains belonging to 15 different wine related yeast species. The technique was further investigated for the identification of yeasts inoculated to sterile grape must as single or in mixtures of two different species. Identical SSCP profiles were obtained from yeasts grown in grape must and in conventional growth media. SSCP allowed obtaining species specific bands, and SSPC profiles from grape must inoculated with mixtures of two strains revealed the presence of specific bands of both species. Direct SSCP yeast analysis of a spontaneous fermenting must carried out after 48 and 192 h of fermentation, enabled to compare the yeast community at two different periods of fermentation. SSCP profiles showed the presence of bands from species associated with the beginning and the end of fermentation, respectively at 48 and 192 h of fermentation. We conclude that SSCP is a quite promising methodology to monitor yeast populations present during grape must fermentation, which revealed to be easy to implement and low-priced.

Keywords : SSCP; rDNA; yeast; population dynamics; grape must fermentation.

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