Determinação de óleos essenciais de alfavaca (Ocimum gratissimum L.), orégano (Origanum vulgare L.) e tomilho (Thymus vulgaris L.)

Abstract

This study aimed to characterize commercial fresh and dry medicinal plants (basil, oregano and thyme), to obtain essential oil by the steam distillation method and to quantify chemical compounds by means of GC/MS. The fresh and dry plants were subjected to the following analyses moisture, ether extract, protein, crude fiber, ash, non-nitrogenous extract, caloric value, essential oil content and identification of major compounds by gas chromatography-mass spectrometry. Considering the obtained characterization, the following results on dry basis proved promising: protein and ash content in commercial dry basil with 17.34 g 100 g -1 and 8.12 g 100 g -1 , respectively; crude fiber in commercial dry oregano with 15.65 g 100 g -1 ; ether extract, non-nitrogenous extract and caloric value in commercial dry thyme with 9.30 g 100 g -1 , 52.72 g 100 g -1 and 356.74 Kcal 100 g -1 , respectively. The highest essential oil yield was obtained for commercial dry basil with 1.02% and the lowest yield was obtained for fresh basil with only 0.13%. Chromatography indicated 87.38% eugenol and 6.27% thymol in fresh basil. For commercial dry basil, the chromatogram showed a reduction in eugenol (71.12%) and an increase in thymol (13.28%). Four peaks were quantified for fresh oregano the -terpinene (33.45%), 4-terpineol (25.59%), thymol (14.21%) and carvacrol (2.30%). For the essential oil of commercial dry oregano, there was a decrease in -terpinene (28.73%) and an increase in 4-terpineol (27.58%), thymol (19.71%) and carvacrol (3.67%). In the chromatogram of the essential oil of fresh thyme, three peaks were quantified: borneol (66.66%), thymol (13.41%) and linalool (3.24%). On the other hand, in the chromatogram of the essential oil of commercial dry thyme, there was a decrease in borneol (37.90%) and an increase in thymol (20.61%) and linalool (10.34%). It can be concluded that commercial dry leaves of basil, oregano and thyme are feasible to enrich foods or to obtain essential oils.