Oa. Antoce et al., A CALORIMETRIC METHOD APPLIED TO THE STUDY OF YEAST GROWTH-INHIBITIONBY ALCOHOLS AND ORGANIC-ACIDS, American journal of enology and viticulture, 48(4), 1997, pp. 413-422
Using a conduction-type isothermal batch calorimeter with 24 units, th
e heat evolved during growth of four yeast strains from different spec
ies in the presence of various concentrations of normal alcohols (C1-C
4) and saturated organic acids (C2, C4, C6, C8, C10) was recorded as g
rowth thermograms. Changes in the growth thermograms were observed whe
n the inhibitor concentration increased, and they were correlated to t
he determined values of the growth rate constant. Subsequent analysis
allowed precise determination of the 50% inhibitory concentration (K-i
) and the 100% inhibitory concentration (MIC) for the growth of the ye
ast strains in the presence of the studied alcohols and acids. The com
bined inhibitory action of ethanol and some acids was also investigate
d, and it was found that ethanol presence leads to a decrease in the K
-i and MIC values of the acids, suggesting an additive or synergistic
activity mechanism. The advantages of the method, as well as influenci
ng factors are also discussed.