STEREOISOMERS OF BETA-METHYL-GAMMA-OCTALACTONE .1. QUANTIFICATION IN BRANDIES AS A FUNCTION OF WOOD ORIGIN AND TREATMENT OF THE BARRELS

The four stereoisomers of oak lactone (beta-methyl-gamma-octalactone) were quantified in different brandies by using multidimensional GC ana lysis. For most of the brandies, the oak origin, the heat treatment an d charring of the barrels, the alcoholic content, and the aging are kn own. The only (3S, 4S) and (3S, 4R) stereoisomers of oak lactone were found in brandies. This study points out the influence of the origin o f the wood for the amount of oak lactone. Brandies matured in barrels made with American white oak contain a greater amount of (3S, 4S)-oak lactone than those matured in barrels made with Quercus robur L. Toast ing and charring of the barrels did not modify the enantiomeric ratios .