Procedures and seasonal variation influencing the yield and quality of the essential oil obtained from Juniperus oxydercus ssp. oxydercus berries
1996
Sousa Vieira, M.
Wild growing Juniperus oxydercus ssp. oxydercus berries collected from Kallergi Crete, Greece, were used to study the effect of the plant material communication, the isolation techniques hydrodistillation and simultaneous distillation extraction and the duration of extraction as well as the different harvesting periods on the yield and composition of the essential oil. The composition of the essential oil was determined by GC and GC/MS analysis. More than eighty components were detected and thirty-three of them, representing approximately 96.50 percent of the total oil, were identified. The major constituents of the oil were a-pinene, b-myrcene, limonene and g-cadinene. The harvesting period and the different extraction procedures proved to have highly significant effects on the essential oil yield of the comminuted berries. The highest yield was obtained in July for the immature berries 2.26 percent and in November for the mature ones 2.39 percent. Two hours of hydrodistillation were sufficient to completely recover the essential oil from the immature berries, whereas three hours were needed for the mature ones. When considering the integral berries, no effects were observed on the essential oil content, and therefore, comminution is a crucial prerequisite for the present plant material. Regarding the essential oil composition, quantitative variations were recorded for both different harvesting periods and extraction procedures as well, in the consideration of the main components. The comminuted immature berries gave the highest content of a-pinene and limonene in November, and b-myrcene and g-cadinene in July. For the comminuted mature berries, November yielded the highest contents for all the components, with the exception of a-pinene, which is highest in February. One hour of hydrodistillation appears to be sufficient for the extraction of the main components, with the exception of g-cadinene from comminuted immature berries, that reaches the maximum yield only after three hours of hydrodistillation
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