Introducing a Simple Method to Investigate Relative Volatilities of Flavour Compounds in Fruit Brandies

Determination of relative volatilities of flavour compounds in hydro-alcoholic solutions is usually performed by time-consuming and costly standard methods such as the Gillespie dynamic recirculation method. This study tested a quick and easy method with a simple distillation apparatus for measuring empirical relative volatilities. A total of 17 representative flavour compounds of apple and pear brandies were selected and investigated for their relative volatilities. This also included so far unpublished relative volatilities of one alcohol (2-butanol), one aldehyde (hexanal), one ketone (& beta;-damascenone), and three esters (ethyl butyrate, butyl acetate, ethyl 2-methylbutyrate). Relative volatilities of three alcohols (methanol, isobutanol, and isoamyl alcohol), one ester (ethyl acetate), one aldehyde (acetaldehyde), and one acetal (1,1-diethoxyethane) were compared to reference data. All compounds, except for 1,1-diethoxyethane, showed a high correlation with the reference data. Vapour-liquid equilibrium for an ethanol-water mixture showed a high correlation with the reference data (r > 0.9). In accordance with the high correlation levels, we suggest that the simple distillation apparatus is a fast and simple alternative to the standard method.