Relationship Between the Sterol Content of Yeast Cells and Their Fermentation Activity in Grape Must

Abstract

In grape must of high sugar concentration, yeast growth, the viability rate of “resting” yeast cells, and fermentation activity were stimulated under certain conditions of aeration and temperature. This stimulation might be interpreted as being a result of the yeast cell sterol content. The addition of certain sterols to the fermenting medium was able to increase this sterol content. According to aeration conditions of the medium, which determined the sterol content of yeasts, the sterols added in the medium acted as (i) growth factors, (ii) fermentation inhibitors, and (iii) survival factors for the yeast.

Genetic improvement  of  thermo-tolerance in wineSaccharomyces cerevisiae  strains by a backcross approach

“…This parameter influences the rate of yeast growth (Watson, 1987), and CO 2 production (Bely et al, 1990a, b;Sablayrolles & Barre, 1993a, b). Temperature also affects cell viability in the late steps of fermentation (Watson, 1987;Sablayrolles & Barre, 1993a) by decreasing plasma membrane H 1 -ATP activity (Alexandre et al, 1993;Piper, 1995) and by changing the fatty acid (Torija et al, 2003;Coleman et al, 2007;Beltran et al, 2008) and sterol (Larue et al, 1980;Beltran et al, 2008) composition of cell membranes. Furthermore, temperature strongly interacts with several fermenting juice parameters such as pH (Ough, 1966a), sugar content (Ough, 1966b), ethanol concentration (Ough, 1966a;D'Amore & Stewart, 1987) and nitrogen composition (Sablayrolles & Barre, 1993a, b).…”

Use and impact of oxygen during winemaking

“…The reason biomass formation is such a concern relates to the need for a timely and efficient completion of fermentation, which is intimately entwined with a robust and active yeast population. An adequate lipid supply not only permits additional cell division but, through augmentation of membrane structure with additional unsaturated fatty acids and sterols, contributes to cellular robustness (Larue et al 1980).…”

Production, reactivation and nutrient requirements of active dried yeast in winemaking: theory and practice

“…This is at least in part because of the impact that anaerobic conditions have on membrane lipid profile, specifically the sterol to phospholipid ratio (Larue et al. ). The relative proportion of membrane ergosterol affects dehydration survival through its influence on membrane plasticity [reviewed in Beney and Gervais ()], a key property in the resistance of cells to dehydration (Dupont et al.…”

“…Most importantly, cellular sterol content is associated with greater viability during the late stages of fermentation, which largely accounts for improved fermentation properties (Larue et al. ).…”