engleski

Hydrodistillation of Essential Oils from Myrtle (Myrtus Communis L.) Leaves Enhanced by Cryogenic Grinding Pretreatment

Myrtle (Myrtus communis L.) is an evergreen aromatic shrub characteristic for Mediterranean area which has long been known for its many positive therapeutic effects. Myrtle leaf essential oil is used in the food and beverage, perfume and cosmetics industries as well as aromatherapy while berries are most commonly used as food spice and in liqueurs production. Myrtle essential oil is produced by water or steam distillation of its leaves, however, due to the low volatiles content, the yield is quite low. Therefore, to minimize the loss of volatile compounds of interest and reduce the particle size to a fine powder, cryogenic grinding at -196 °C can be used as an innovative grinding technique and a pre- treatment for the distillation. The influence of cryogenic grinding of myrtle leaves on the essential oil yield, quality and quantity of its components obtained by distillation on a Clevenger apparatus was investigated with the aim of shortening the distillation time and obtaining an essential oil with better properties. Cryogenic grinding of myrtle leaves was performed at 3, 6 and 9 minutes with untreated leaves used as control and the distillation time was set at 30, 60 and 90 minutes. GC-MS analysis of myrtle essential oil was able to detect and quantify 22 volatile constituents, mainly terpenoids, where the dominant compounds were 1, 8-cineol, myrtenyl acetate, α-pinene and linalool. Cryogenic grinding applied for 3 minutes, compared to the control, was able to significantly increase the yield and concentrations of individual compounds. This effect was specifically notable for low- boiling-point volatile compounds such as α- pinene, myrcene and 3-carene which concentrations increased 26.0, 28.2 and 28.9%, respectively, while total volatiles content increased by 9.8%. On the other hand, longer grinding time caused decrease of high-boiling- point volatile compounds and lower total volatiles content compared to the control. Considering the interaction of grinding and distillation time, total volatiles were the highest with 3 minutes of cryogenic grinding and 30 minutes of distillation yielding 18.1% more than with control in the same time period.

myrtle ; essential oil ; cryogenic grinding ; 1, 6-cineol ; myrthenyl acetate

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