Bound aroma compounds from the fruit and the leaves of blackberry (Rubus laciniata L.)

Abstract

HRGC and HRGC-MS identifications of bound aroma compounds from the fruit and the leaves of blackberry (Rubus laciniata L.) were achieved after isolation of extracts obtained by Amberlite XAD-2 adsorption and methanol elution followed by hydrolysis with a commercial pectinase enzyme. In the fruit 41 aglycons and in the leaves 32 bound aroma compounds were identified. Quantitative HRGC revealed 5.8 mg/kg of aglycons in the fruit, whereas 56.1 mg/kg were determined in the leaves. Major constituents comprised benzyl alcohol, benzoic acid, 3-hydroxy-7,8-dihydro-beta-ionol, (Z)-3-hexen-1-ol, and the diastereomeric vitispiranes. Chiral evaluation of enzymatically liberated aroma compounds carried out by on-line multidimensional capillary gas chromatography-mass spectrometry (MDGC-MS) revealed the occurrence of enantiomerically pure (S)-2-heptanol both in the fruits and in the leaves as well as 2-methyl-2-hepten-6-ol in the enantioselective distribution of R:S = 82:18% in the leaves.