جستجوی مقالات مرتبط با کلیدواژه « به لیمو (lippia citriodora h » در نشریات گروه « باغبانی »

To evaluate the effect of air velocity and infrared radiation intensity on drying time, essential oil content, and composition of Lemon Verbena (Lippia citriodora Kunth), a factorial experiment based on completely randomized design was carried out. The two main treatments were as follows: three air velocity levels (0.5, 1 & 1.5m/s) and three levels of infrared radiation intensities (0.2, 0.3 & 0.5W/cm2). After drying the samples, their essential oil was extracted by hydro-distillation method and compositions of essential oil were identified with capillary gas chromatography, using flame ionization and mass spectrometric detection. Results indicated that the various treatments had significant effects on drying time and essential oil content. With decreasing air velocity and increasing radiation intensity, drying time was reduced. Minimum drying time (35 minutes) was obtained at 0.5 m/s air velocity with the use of 0.5W/cm2 radiation intensity. In contrast, the maximum drying time (65 minutes) was revealed for the sample treated with 1.5 m/s air velocity, which received concomitantly 0.4W/cm2 radiation intensity. Increasing the intensity of infrared radiation in all air velocities had a significant effect on the essential oil content, so that the maximum essential oil content (1.1%) was obtained by application of 1 &1.5 m/s air velocity and the use of 0.5W/cm2 radiation intensity. The survey of essential oil components showed that the highest amount of oxygenated monoterpenes (73.3%), especially citral (61.3%) was measured from samples dried by 0.5 m/s air velocity and 0.2W/cm2 radiation intensity. According to these results, due to the decreased duration of drying time and desired essential oil content and composition, it seems that the use of infrared radiation in conventional dryers could lead to appropriate quality of essential oil.

Lippia citriodora H. B. et K. is a valuable medicinal plant whose extract, as its main chemical composition, has active components such as Geranial and Limonene widely used in pharmaceutical, food, cosmetic and health industries. In medicinal plants, balanced fertilization using chemical and biological inputs has great effect on yield and phytochemicals related to yield production. This study was conducted in the greenhouse of Tarbiat Modares University. In this experiment, seven treatments were performed in a completely randomized block design with three replications. The aim of this study was to investigate the effects of balanced fertilization and super-absorbent polymer on the chemical components and yield of Lippia citriodora. After planting and harvesting operations and growth performance measurements, essential oil was dehydrated by distilled water method using Clevenger and Sodium sulfate. Using gas chromatography and gas chromatography connected to spectrum, 15 compounds were determined in essential oil, consisting more than 90% of essential oil components. Results showed that there was a significant difference among treatments (p< 0.01). The lowest and highest fresh yield were related to control (6410 kg.ha-1) and balanced fertilization + bio-fertilizer + super-absorbent polymer (15435 kg. ha-1) treatments, respectively. The lowest and highest dry leaf yield were obtained in control (702 kg.ha-1) and balanced fertilization + bio-fertilizer + super-absorbent polymer (1503 kg. ha-1) treatments, respectively. The lowest and highest essential oil content was achieved in control (7.4 kg.ha-1) and balanced fertilization + bio-fertilizer + super-absorbent polymer (20.5 kg.ha-1) treatments, respectively. In terms of overall essential oil components, the minimum and maximum contents of Neral and Geranial were obtained in control and balanced fertilization treatments with 41.2% and 52.27%, respectively.

Lemon verbena (Lippia citriodora H. B. et K.) is one of the medicinal plants, belonging to the family Verbenaceae. This plant has active ingredients with sedative, anticonvulsant, heartbeat away, anti-diarrhea and antimicrobial effects. Accurate drying of medicinal plants is inevitable in order to reduce the humidity and increase the longevity and quantity and quality of the active ingredients. In this research, hot air dryer was used to dry the leaves of lemon verbena by using temperatures of 30, 40 and 50ºC and different air speeds of 0.5, 1 and 1.5 m/s to reach a humidity of 15%. Essential oil was extracted by Clevenger apparatus. Results showed that effects of temperature and air speed and their interaction on drying time were significant. Results of mean comparisons showed no significant difference between the temperatures of 40ºC and 50ºC. With increase of temperature, the effect of air speed was negligible. The best treatment in terms of minimum drying time was 40ºC and 1 m/s speed. Different levels of temperature showed significant effect on quantity of the essential oil as the highest and the lowest essential oil level were respectively obtained at 30ºC and 40ºC. The speed of the hot air also showed a significant effect on quantity of the essential oil as the maximum essential oil was obtained at the speed of 0.5 m/s. The results of interaction effects showed that maximum essential oil obtained at 500C temperature and 0.5 m/s speed. Finally, 7 Mathematical models of thin layer drying for different conditions such as R2, SSE and RMSE were compared. According to the results, Modified Page was identified as the best model for drying lemon verbena.