The effect of air-drying on glycosidically bound volatiles from seasonallycollected origano (Origanum vulgare ssp hirtum) from Croatia

The glycosidically bound volatiles were isolated from fresh and air-dried o rigano by exhaustive percolation with ethyl acetate. After the purification of glycosidic fraction, the enzymatic hydrolysis with beta -glucosidase wa s performed. The obtained aglycones were analysed by GC-MS. Eighteen compou nds were identified. The seasonal variations of main aglycone contents from the fresh plant material were: thymo-quinone (3.10-6.18 mg/kg), benzyl alc ohol (1.33-3.62 mg/kg), 3,5,5-trimethyl-4-(3-hydroxy-1-buthenyl)-2-cyclohex en-1-on (0.51-3.35 mg/kg), 2-phenyl ethanol (0.42-2.98 mg/kg), eugenol (0.9 3-2.55 mg/kg), thymol (0.70-1.40 mg/kg) and carvacrol (0.88-1.40 mg/kg). Th e season of collecting influenced the content and composition of the glycos idically bound volatiles of origano. Air-drying effected mostly the yield o f these compounds.