Influence of the distillation rate on the quality and quantity of essential oil from Rosa alba L.

A. Dobreva*

Institute of Roses, Essential and Medical Plants, 49 Osvobojdenie, 6100 Kazanlak, Bulgaria

Abstract. The aim of the investigations was to trace the influence of the speed level on the distillation of white oil-bearing rose. Using the methods of direct distillation of fresh rose flowers, it has been found that increasing the pressure and the flow rate of the distillate high yield can be achieved, but deterioration of thequalityoftheessentialoilisobserved.TheoptimalrateofprocessingforRosaalbaL.is8–10%. Inthiswaytheyieldisrisingupto0.02%andthevalueof the ratio of terpene alcohols / hydrocarbons is enhanced up to 0.74.

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Influence of the temperature for distillation on the yield and quality of the Rosa alba L. essential oil

A. Dobreva*

Institute for Roses and Medicinal Plants, 49 Osvobojdenie, 6100 Kazanlak, Bulgaria

Abstract. Applying the method of distillation, the influence of different temperatures at the outlet of the cooler when processing Rosa alba is traced. It has been found that the extraction temperature rise leads to an increase of the yield by 10%, but losses of essential oil components up to 33% are detected. Gas chromatography assay revealsthattemperaturerateat24÷28oC keepsthemaximumoftheterpenealcohol citronellol+nerolandgeraniol(13.52%and15.4 %, respectively), so this temperature level can be recommended.

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Content and composition of the essential oil of Rosa alba L. during flower development

A. Dobreva, M. Gerdzhikova
Abstract. In 2010 the content and composition of the essential oil from Rosa alba L. in the different phases of the development of blossom is examined. Quantitative and qualitative changes of the essential oil are traced. Flowers from the population of white rose in 6 phases were investigated. The study was conducted at the Institute of roses and essential oil plants Kazanlak. It was found that optimum for the quantity and quality of the essential oil is not exactly at one time, but there is a correlation between the two indicators. The maximum content of essential oil is in phase IV – in semi-opened petals (in %). Optimal composition was recorded in (IV) and (V) phase, where the fundamental terpene alcohols: citronelol + nerol and geraniol are within limits, respectively 21,33 ÷ 22,19% and 8,11 ÷ 8,02% and the values of the ratio of terpene alcohols/hydrocarbons are the largest. White rose must be picked in semi-opened and opened flowers stage. After detachment of flowers processes of biosynthesis in the tissues continue and in storage both phases are matched. Thus optimal conditions for accumulation of maximum quantities of quality essential oil are created.

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Daily dynamics of the essential oils of Rosa damascena Mill. and Rosa alba L.

The dynamics of the essential oils of Rosa damascena Mill. and Rosa alba L. within a day period has been measured. It has been found that the two genotypes have the same rhythm in the release of volatile emissions. In the context of meteorological conditions the maximum of oil of the pink rose was reached at 8 o’clock (0.275 %), and that of the white rose – at 12 o’clock (0.216%). The quality and quantity changes in oil run parallel. The white rose has the potential to synthesize a high percentage of terpene alcohols – up to 43.97% (compared to 42.48% for the pink rose), but is more unstable in this potential.

Daily dynamics of the essential oils of Rosa damascena Mill. and Rosa alba L.

A. Dobreva, N. Kovacheva