Use of Microwave-assisted Hydrodistillation to Extract the Essential Oils from Satureja hortensis and Satureja montana

Abstract

Microwave-assisted hydrodistillation (MAHD) has recently been attended for the extraction of essential oils from medicinal plants/herbs. In this study, MAHD was investigated for the extraction of essential oils from two genotypes of savory (Satureja hortensis, so-called summer savory, and Satureja montana, socalled winter savory). Three levels of microwave power (220, 440 and 660 W) were selected for the extraction. MAHD resulted in a shorter extraction time compared to that in HD. Total extraction times at 660 W microwave power was 180 min for S. hortensis and 90 min for S. montana. The extraction yield obtained by MAHD was almost equal to that obtained by HD (3.1%, w/w, for S. hortensis and 0.7% for S. Montana). Extraction was more efficient at higher power levels.Keywords: essential oils, microwave-assisted hydrodistillation, Satureja hortensis, Satureja montana, savory *To whom correspondence should be addressed. Email: krezaee@ut.ac.ir IntroductionThe use of herbs and plants in food industry has a long history. The diversity among the components of the plants has resulted in their use in many applications including in flavors and fragrances as well as in medicine. Essential oils are among the secondary metabolites produced within the various organs of medicinal herbs/plants. They are complex mixtures of volatile compounds such as terpenes (mostly monoterpenes and sesquiterpenes), phenolics and alcohols . The conventional method for the extraction of essential oils is hydrodistillation (HD), in which the essential oils are evaporated by heating a mixture of water and plant materials followed by the liquefaction of the vapors in a condenser. However, this method suffers from several disadvantages including losses in the volatile compounds, long extraction time and degradation of some components through thermal and/or hydrolytic effects (Khajeh et al., 2004;. Because of these shortcomings, newer approaches such as microwave-assisted extraction (MAE,) with or without the use of a solvent, have been developed. MAE, for example, has been applied for the extraction of cocaine and benzoylecgonine from coca leaves by using both polar and nonpolar solvents (Brachet et al., 2002). MAE has also been investigated for the extraction of essential oils from several herbs including artemisia (Hao et al., 2002), caraway seeds (Chemat et al., 2005), orange peel (Ferhat et al., 2006), lavender (Chemat et al., 2006, and cardamom (Lucchesi et al., 2007). Another extraction method in this area is microwave assisted hydrodistillation (MAHD,) which is an advanced hydrodistillation method based on the use of a microwave oven. This technique has recently been investigated in the extraction of volatile secondary metabolites from Lippia Alba (Stashenko et al., 2004a) and Xylopia aromatica (Stashenko et al., 2004b). The efficiency of MAHD is strongly dependent on the dielectric constant of water and the matrix (Brachet et al., 2002). MAHD causes the rapid delivery of energy to the total volume of solvent/ sample leading to a rapid rise ...

Antibacterial properties and chemical characterization of the essential oils from summer savory extracted by microwave-assisted hydrodistillation

“…Data showing the lengths of times needed by MAHD and HD to reach the extraction temperature (so-called induction Antibacterial properties of the essential oils from summer savory times) and those indicating the total recoveries of essential oils at different power levels were published elsewhere (21). For MAHD at 660 W, the extraction started much earlier than that for HD.…”

Effect of microwaves on the in situ hydrodistillation of four different Lamiaceae

“…Over the last few years, more laboratories have successfully applied microwave-assisted extraction (MAE) [2,3] and in situ microwave-generated hydrodistillation (MGH) [4], which are both now well recognized as innovative green and efficient techniques [5]. Dielectric heating is a nonclassical energy source that is capable of reducing extraction times because of its selective volumetric heating that also gives excellent product quality [6,7].…”

Comparative Studies of Different Extraction Methods of Essential Oil From Matricaria Recutita L. In Iran

“…The required time to reach the boiling point of water at 540 W was nearly one-fourth of that at 180 W. After 20 minutes of operation, the extraction yield at 540 W (1.53%, w/w) was about five times more than that at 180 W (0.31%, w/w). Meanwhile, the extraction yield for 540 W after 45 minutes of operation was the same as that obtained in 60 minutes at 360 W [22]. In another study, Özek et al (2005) extracted essential oils of three endemic Turkish Heracleum species by different techniques.…”

“…They found that for the same extraction yield, the time required for microwave-assisted hydro-distillation was one-fourth of that for hydro-distillation [21]. Rezvanpanah et al (2008), extracted essential oils from Satureja hortensis and Satureja montana using microwave-assisted hydro-distillation, where the extraction time was reduced significantly as the microwave power was changed from 220 to 660 W. The difference in the extraction yield at 180 and 540 W seemed to be more pronounced during the first 2 hours of extraction. The required time to reach the boiling point of water at 540 W was nearly one-fourth of that at 180 W. After 20 minutes of operation, the extraction yield at 540 W (1.53%, w/w) was about five times more than that at 180 W (0.31%, w/w).…”