Presence and Significance of Two Diastereomers of β-Methyl-γ-octalactone in Aged Distilled Liquors

Abstract

Two diastereomers of β-methyl-γ-octalactone were identified as aging aroma substances from the neutral ethyl acetate extract of aged brandy. It was shown by means of gas liquid chromatography that they were derived from the oak barrels and were accumulated in the distilled liquor during the aging process. The organoleptic threshold of cis-lactone was 0.79ppm and that of trans-lactone was 0.067ppm. The aroma of cis-lactone was more fragrant than that of trans-lactone.
The amount of β-methyl-γ-octalactone in various wood powders was determined comparatively, and the precursor of the lactone was identified in oak wood.
Moreover, a positive correlation between the organoleptic evaluation of whisky and the amount of trans-lactone was recognized.