THE INFLUENCE OF THE COMPOSITION OF MODEL LIQUID CULTURE-MEDIUM ON VAPOR LIQUID PARTITION-COEFFICIENT OF AROMA SUBSTANCES

In order to throw into relief variations in the volatility of aroma su bstances in a liquid culture medium in relation to its composition, vo latility, as expressed by the vapour-liquid partition coefficient, was measured by the head-space method, in media of variable composition ; 3 aroma substances - ethyl acetate, 2.5 dimethylpyrazine and oct-1-en -3-ol were involved. The study of the influence of seven factors using a Rechtschaffner matrix of experiments enabled us to show that, in th e experimental field under study and in relation to pure water: 1) Tem perature and the presence of a fatty acid have a primordial and invers e effect, 2) volatility increases with the quantity of salts such as ( NH4)2SO4 et KH2PO4, 3) glucose, a mixture of amino acids and micro-ele ments, as well as the pH have little effect. The importance of the eff ects of each factor varies according to the nature of the aroma substa nces.