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ENOLOGICAL APTITUDE OF SACCHAROMYCES CEREVISIAE X SACCHAROMYCES UVARUM ARTIFICIAL HYBRIDS
ORIGONE A.; RODRÍGUEZ M.E; GOMEZ JE; LOPES C.A.
Jornada; V Jornadas Sudamericanas de Biología y Biotecnología de Levaduras; 2015
Saccharomyces cerevisiae (Sc) is the yeast species responsible for conducting most winemaking processes in the world, although Saccharomyces uvarum (Su) and in lesser extent natural hybrid strains between Sc and Su have been also detected in these fermentations, particularly those carried out at low temperature. The aim of this work was to evaluate the enological aptitude of hybrid strains artificially obtained from a wine selected strain of Sc and two strains of Su obtained from different origins: Sua isolated from Araucaria araucana and Such isolated from chichas in North Patagonia. Hybrids were obtained by rare-mating and stabilized by means of successive fermentations in grape must at 13°C and 20°C. One hybrid strain obtained from each cross and temperature was selected to carry out fermentations in 1L of inoculate Sauvignon blanc grape juice (170 °Brix) at both (13°C y 20°C) temperatures. Fermentations were monitored by ºBrix and sugar content (using enzymatic kits) measures. All strains consumed completed the fermentations after 12 and 8 days of fermentation at 13ºC and 20ºC, respectively. The content of ethanol, glycerol, organic acids, higher alcohols and esters was evaluated in the resulting wines. In general, no differences were observed in wines produced at the two temperatures. Sc produced levels of ethanol significantly higher than the rest of strains at 13ºC and 20ºC (9.53±0.07b and 9.33±0.28b % v/v, respectively) while Su, particularly Such at 20°C, produced the highest levels of glycerol. Additionally, the wines fermented with Sc showed the highest levels of hexyl acetate, ethyl octanoate, 1-hexanol and isoamyl acetate, and those fermented with Su showed the highest concentrations of 2-phenylethanol and shikimic acid. Wines obtained with the hybrids showed the highest concentrations of 1-propanol, independently from the temperature and the Su parental. In Malbec grape must (240° Brix), only the hybrids completed the fermentations at 13ºC and only Sc at 20ºC. In summary, independently from the temperature of fermentation and the Su parent involved in the cross, the hybrids showed homogeneous and differential characteristics than those of the parental strains Sc y Su, evidencing a huge potential to be used as starter cultures for winemaking at low temperature.