Dados do Trabalho

Título

INDIGENOUS YEAST IN SAUVIGNON BLANC WINES: GROWTH KINETICS AND INCREASE IN THE CONCENTRATION OF PHENOLIC COMPOUNDS

Introdução

The demand for wines that have the typicality and complexity of a terroir is on the rise among consumers, encouraging spontaneous fermentations, or fermentation with the co-culturing candidate yeasts in the biodiversity of the vineyards with commercial yeasts. The main objective of this study was to investigate the growth kinetics of Saccharomyces cerevisiae selected from vineyards of the “Vinhos de Altitude” region during the vinification of Sauvignon blanc must and evaluate the effect of fermentation on the concentration of phenolic compounds.

Material e Métodos

Sauvignon blanc grapes from São Joaquim, Santa Catarina, Brazil (latitude -28º, 14' 9.7”, longitude -50º, 4” 16.7”, altitude 1,200 meters) were harvested with 22 ºBrix, de-stemmed, pressed and the must was clarified. The control experiment (C) was fermented with strains of Saccharomyces cerevisiae (Zymaflore® CX9, Laffort, France). Experiment A was fermented with five indigenous strains of Saccharomyces cerevisiae, isolated from vineyards in the “Vinhos de Altitude” region. Experiment B was fermented with five indigenous strains of Saccharomyces cerevisiae and one inoculum of Saccharomyces cerevisiae CX9. The fermentation process was carried out in 10 liters reactors and monitored for 9 days by yeast counts in YPD medium. The determination of phenolic compounds was carried out by high-performance liquid chromatography (HPLC-DAD). Browning index was evaluated by spectrophotometry.

Resultados e Discussão

The population of Saccharomyces cerevisiae increased immediately, showing no observable lag phase. All growth curves developed exponential and stationary phases, whose growth kinetics can be described by a three-parameter logistic model. There was no significant difference in the specific growth rates during the fermentation of Sauvignon blanc wines. Wine A showed a higher concentration of 4-hydroxybenzoic acid, (-)-epicatechin, ferulic acid, rutin, tyrosol and trans-resveratrol when compared to wine C. Sequential inoculation and fermentation (wine B) increased the concentration of (+)-catechin, 4-hydroxybenzoic acid, ferulic acid, gallic acid and p-coumaric acid in relation to Sauvignon blanc must. There was no significant difference between wines A (0.093), B (0.092) and C (0.105) after one year of storage in the bottle, regarding the browning index.

Conclusão

These results suggest that indigenous Saccharomyces cerevisiae are efficient for fermenting Sauvignon blanc wines, increasing flavonoid and non-flavonoid content, without promoting oxidative browning.