Cultivation conditions preferable for yeast cells to be immobilized into poly(vinyl alcohol) and used in bottled sparkling wine production

Abstract

An effective approach to the improvement of the biochemical status of yeast cells before their immobilization was applied to develop a biocatalyst with a high level of cell metabolic activity and viability that could be used for sparkling wine production. According to the approach, the wine-containing medium (pH 3.0) routinely used for the accumulation of champagne yeast biomass under aerobic conditions was replaced by a semi-synthetic one (pH 5.6), usually applied for aerobic yeast growth. The variation of temperature and pH conditions of cell growth showed a modification of the fatty acid pool of yeasts and its importance for the further immobilization of cells into a poly(vinyl alcohol) cryogel. Measurement of the specific intracellular ATP concentration by the bioluminescent method revealed the growth phase favorable for yeast immobilization. The main characteristics of the sparkling wine obtained after four-week fermentation with application of both the free and immobilized cells were similar but, according to the detected energetic status, the viability level of the immobilized cells was considerably higher compared to the free yeast. The CO2 pressure accumulated in the bottles with immobilized cells (up to 500 kPa) after fermentation also appeared notably higher than in the bottles with free yeast.

Biotechnologies in sparkling wine production. Interesting approaches for quality improvement: A review

“…Efremenko, Stepanov, Martinenko, and Gracheva (2005), determined the cell growth conditions in order to ensure yeast biomass accumulation for the further development of an efficient biocatalyst for sparkling wines production, poly(vinyl alcohol) cryogel (PVA CG) was used in order to entrap yeast cells. The cultivation conditions used for biomass accumulation before its immobilisation could affect the biocatalyst features and, thereby, the characteristics of sparkling wine production.…”

Application of Immobilized Yeasts for Improved Production of Sparkling Wines

“…Early decay determined the more rapid autolysis of immobilized yeasts [26]. Moreover, an increase in the content of amino acids in the sparkling wines elaborated with immobilized yeasts was observed.…”

“…The results showed that there were no significant differences in pH, total and volatile acidities, reducing sugar, and alcoholic strength between both inoculation formats (free and immobilized yeasts). Some authors have also reported that the use of immobilized yeasts did not affect the enological parameters of the sparkling wines [4,9,13,26]. Moreover, it has been reported that the Ca-alginate entrapment technique did not cause notable changes in the main analytical composition of bottle-fermented sparkling wines [27][28][29].…”