Absolute configuration of octanol derivatives in apple fruits.

In extracts obtained by liquid-liquid extraction and enzymatic hydrolysis from five apple cultivars (Renao; Bedan; Peau de Chien; Noel des Champs; Red Delicious), chiral evaluation of free and glycosidically-bound octane-1,3-diol and 5(Z)-octene-1,3-diol, as well as ethyl 3-hydroxyoctanoate and ethyl 5(Z)-3-hydroxyoctenoate, was performed by multidimensional gas chromatography (MDGC), combining a polar achiral column (DB-Wax) with a chiral main column (2,3-di-O-acetyl-6-O-tert. butyldimethylsilyl-beta-cyclodextrin/OV 1701). Comparison of retention times of synthesized optically-enriched reference compounds with isolated diols and hydroxyesters, revealed the (R)-configuration for the free diols in cvs. Renao, Bedan, Peau de Chien and Noel des Champs and the (R)-configuration for the bound diols in cvs Bedan, Peau de Chien and Noel des Champs, exhibiting enantiomeric excesses (ees) greater than 99%. (R)-hydroxyesters (ee > 99%) were detected in cvs. Noel des Champs and Red Delicious.