Combined effects of sulfites, temperature, and agitation time on production of glycerol in grape juice by Saccharomyces cerevisiae

Abstract

Analysis of variance was used to evaluate the simultaneous effects of strain, incubation temperature (15 to 25°C), agitation time (0 to 24 h), and initial sulfite concentration (100 to 300 ppm) on glycerol production in grape juice by Saccharomyces cerevisiae. Fourteen strains were studied to determine their growth patterns in the presence of sulfites and ethanol. Baker's yeast strains were more sensitive to sulfite than wine strains, and little growth occurred at initial sulfite levels greater than 150 ppm. Sensitivity to sulfite increased with increasing levels of ethanol. Three strains exhibiting the best growth in the presence of sulfites and ethanol were selected for interaction studies. Fermentations were carried out until the solids content had decreased to less than 6°Brix, which was the point that glycerol content became stable. For the three strains used, the greatest level of glycerol production was observed in the presence of 300 ppm of sulfite for most incubation temperatures and agitation times. There was significant interaction between the strain, incubation temperature, and agitation time parameters for glycerol synthesis, and a response surface method was used to predict the optimal conditions for glycerol production. Under static conditions, the highest level of glycerol production was observed at 20°C, while incubation at 25°C gave the best results when the cultures were agitated for 24 h. Response surface equations were used to predict that the optimum conditions for glycerol production by S. cerevisiae Y11 were a temperature of 22°C, an initial sulfite concentration of 300 ppm, and no agitation, which yielded 0.68 g of glycerol per 100 ml. * Corresponding author. t Centre de Recherche et Developpement sur les Aliments contribution 283.

Optimisation of fermentation conditions for mango (Mangifera indica L.) wine production by employing response surface methodology

“…Glycerol production by yeast is influenced by many growth and environmental factors (Albers et al, 1996;Remize et al, 2000). Several studies have shown that an increase in temperature resulted in higher glycerol production (Gardner et al, 1993;Remize et al, 2000). It is reported that the optimum temperature for maximum glycerol production by commercial wine yeast strains of S. cerevisiae varies between 22°C and 32°C (Scanes et al, 1998).…”

“…Glycerol is the most abundant by-product of wine fermentation after ethanol and carbon dioxide. This polyalcohol does not directly contribute to wine aroma due to its nonvolatile nature, but it contributes to sweetness, fullness and smoothness (Gardner et al, 1993;Remize et al, 2000;Taherzadeh et al, 2002). Typical glycerol levels in wine are given as 1-15 g L )1 , with average values approximately 7 g L )1 (Taherzadeh et al, 2002).…”

Comparative metabolic footprinting of a large number of commercial wine yeast strains in Chardonnay fermentations

“…For a given starting juice, this footprint can change due to the yeast strain used or the environmental conditions of the fermentation. Previous studies have shown that different S. cerevisiae wine yeast strains fermenting the same juice under identical conditions can yield very different wines due to differences in the metabolic footprint (Gardner et al, 1993;Romano et al, 1994Romano et al, , 2003Benitez et al, 1996;Mortimer, 2000;Remize et al, 2000;Torrea & Ancin, 2002;Fleet, 2003). However, most of these studies compared only a small number of yeast (< 10) and/or a small number of metabolites (< 20), often in synthetic must or media, thereby not giving a true representation of a grape fermentation.…”

A comparative study of the wine fermentation performance of Saccharomyces paradoxus under different nitrogen concentrations and glucose/fructose ratios

“…Because of the favourable impact on wine quality, glycerol production is one of the desir-able features in wine yeast selection. Glycerol production by yeast is affected by many growth and environmental factors (Gardner et al 1993;Remize et al 2000). This metabolite is synthesized by yeasts in response to a hyperosmotic medium.…”