Optimizing aroma compound fractionation in pear brandy distillation by controlling their relative volatility

Abstract

This study aims at improving the fractionation of key odor compounds in pear brandies by controlling their relative volatility through novel fractionation strategies. Two approaches were tested: one using a high cooling water flow rate at the dephlegmator with a slow distillate flow and another employing a distillation column with 12 trays. Both effectively elevated ethanol concentration on the top tray, altering the relative volatility of compounds in the liquid phase and influencing the final product composition. The behavior of compounds closely aligned with their relative volatility data. Elevated ethanol concentrations reduced the relative volatility of higher alcohols, delaying their release from the column and producing sharper peaks compared to the broader profiles in the control distillation. This enabled the effective separation of beta-damascenone and ethyl (E,Z)-2,4-decadienoate (pear ester) from higher alcohols, creating an aroma-rich tails fraction enriched with these desirable compounds. Mixing this tails fraction with the hearts fraction produced a blend that was significantly preferred in sensory evaluations over the standard hearts fraction. These findings highlight the importance of tailoring ethanol profiles in the distillation apparatus to optimize compound separation and enhance the quality of pear brandies.