The combination effect of pH, SO ₂ , ethanol and temperature on the growth of <i>Leuconostoc oenos</i>

Abstract

A factorial design was used to determine the main effects and interactions of pH (3.6, 3.8 and 4.0), SO 2 (25 and 50 mg/l), ethanol (7%, 10% and 13%, v/v) and temperature (15°C and 25°C) on the growth of 54 Leuconostoc oenos strains. These differed greatly in their ability to survive adverse conditions. Under the test conditions, temperature had a profound effect on growth. The power pH values of 3.6 and 3.8 had a marked inhibitory effect on growth, as did at the lower temperature of 15°C. The higher concentrations of SO 2 (50 mg/l) and ethanol (13%) had the greatest inhibitory effect on growth, and with a synergistic effect when both SO 2 and ethanol were added to the test medium. Based on these results, five strains were selected that were best capable of surviving the adverse conditions studied. These strains will be used for further study on the induction of malolactic fermentation in wine.