PT  - JOURNAL ARTICLE
AU  - M. Malfeito-Ferreira
AU  - J. P. Miller Guerra
AU  - V. Loureiro
TI  - Proton Extrusion as Indicator of the Adaptive State of Yeast Starters for the Continuous Production of Sparkling Wines
AID  - 10.5344/ajev.1990.41.3.219
DP  - 1990 Jan 01
TA  - American Journal of Enology and Viticulture
PG  - 219--222
VI  - 41
IP  - 3
4099  - http://www.ajevonline.org/content/41/3/219.short
4100  - http://www.ajevonline.org/content/41/3/219.full
SO  - Am J Enol Vitic.1990 Jan 01; 41
AB  - A rapid test to evaluate the adaptive state of active dry yeast (ADY) starters used in continuous sparkling wine production is proposed. This method is based on the determination of an exponential constant of ethanol-enhanced passive proton diffusion across the yeast plasma membrane, which can be estimated rapidly and easily. A correlation was found (correlation coefficient = 0.929) between the enhancement constant k and the specific death rate of yeast populations (harvested at different stages of starter preparation) cultivated in tirage conditions under 5.1 ± 0.1 x 105 Pa CO2 pressure. The results support the method validity and suggest the importance of an ADY adaptation prior to tirage inoculation.