Extraction of Essential Oils of Rosmarinus officinalis L. by Two Different Methods: Hydrodistillation and Microwave Assisted Hydrodistillation

Hindawi e Scientific World Journal Volume 2019, Article ID 3659432, 6 pages https://doi.org/10.1155/2019/3659432 Research Article Extraction of Essential Oils of Rosmarinus officinalis L. by Two Different Methods: Hydrodistillation and Microwave Assisted Hydrodistillation Majda Elyemni ,1 Bouchra Louaste,2 Imane Nechad,1 Taha Elkamli,3 Abdelhak Bouia,2 Mustapha Taleb,4 Mahdi Chaouch,1 and Noureddine Eloutassi1 1 Laboratory of Materials Engineering and Environment, Faculty of Sciences Dhar El Mahraz, Sidi Mohammed Ben Abdellah University, BP 30003, Fez, Morocco 2 Laboratory of Biotechnology, Faculty of Sciences Dhar El Mahraz, Sidi Mohammed Ben Abdellah University, BP 30003, Fez, Morocco 3 Laboratory of Biological Test, Food and Nutritional Transition Team (ETAN), Ibn Tofail University, BP 133, Kenitra, Morocco 4 Laboratory of Engineering, Electrochemistry, Modeling and Environment, Faculty of Sciences Dhar El Mahraz, Sidi Mohammed Ben Abdellah University, BP 30003, Fez, Morocco Correspondence should be addressed to Majda Elyemni; Received 26 November 2018; Revised 7 February 2019; Accepted 5 March 2019; Published 1 April 2019 Academic Editor: Paula B. Andrade Copyright © 2019 Majda Elyemni et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited. The extraction of essential oils is generally carried out by two main techniques: azeotropic distillation (hydrodistillation, hydrodiffusion, and steam distillation) and extraction with solvents. However, these traditional methods are a bit expensive, especially since they are extremely energy and solvent consuming. This work consists in studying two methods of extraction of the essential oils of Rosmarinus officinalis L.: microwave assisted hydrodistillation (MAH) and Clevenger hydrodistillation (CH). Several parameters have been studied: the extraction time, the yield, and the chemical composition of the essential oils as well as the efficiency and cost of each procedure. The results obtained revealed that microwave-assisted hydrodistillation makes it possible to minimize the extraction time of the essential oils in comparison with conventional hydrodistillation. Thus, the same yield of essential oils is obtained for 20 minutes only with MAH while it takes 180 minutes with CH. In addition, the quality of the essential oil is improved thanks to a 1.14% increase in oxygenates. In conclusion, the MAH method offers significant advantages over conventional hydrodistillation and can therefore replace it on a pilot and industrial scale. 1. Introduction Rosmarinus officinalis L., commonly known as rosemary, is a shrub belonging to the Lamiaceae family and native to the Mediterranean basin[1]. This plant has been widely used in traditional medicine since antiquity, and it has also been used as a food preservative and flavoring agent [2, 3]. Rosemary contains an essential oil to which it owes its interesting properties. It is known for its antioxidant, antimicrobial, anti-inflammatory, anticarcinogenic, antidiabetic [4], antinociceptive [5], and antithrombotic properties [6] and antiulcerogens [7], diuretics [8], and hepatoprotective effects [9]. These biological properties have made rosemary a potential new therapeutic agent in the treatment of many diseases. One of the main derivatives of this emblematic plant in traditional medicine is its essential oil. The essential oil secreted by glandular trichomes is mainly located in leaves and the flowers; the highest quality essential oil is obtained from the leaves [10]. Rosmarinus officinalis L. essential oil is usually isolated by hydrodistillation, steam distillation, or extraction with organic solvents. These techniques cause the loss of certain volatile compounds due to long extraction times and degradation of unsaturated or esterified compounds by thermal or hydrolytic effect. For example, monoterpenes may be susceptible to chemical changes under stream distillation conditions and even the conventional solvent extraction during removal of solvent by distillation. In addition, many 2 of these methods are time-consuming and energy intensive [10, 11]. However, in order to reduce the extraction time and improve the quality of essential oils, new extraction techniques have been developed such as microwave assisted extraction, solvent extraction under pressure, supercritical fluid extraction, and ultrasound-assisted extraction [12, 13]. Microwave-assisted hydrodistillation has been used for the extraction of laurel essential oils [14], lavender [15], and thyme [16], and rosemary has also been studied [17, 18]. Faced with all these innovative methods of extraction of essential oils, the choice of the most efficient method is relevant for a better optimization of time, yield, and cost of production. This work aims to make a comparative study of two methods of extraction of essential oils of Moroccan Rosmarinus officinalis L.: conventional hydrodistillation and microwave assisted hydrodistillation. These two methods were chosen to study the effect of microwave energy on the quantity and quality of rosemary essential oil. In addition, the cost, energy consumption, and environmental impact have been optimized in order to have an optimal method for the production of essential oils of better quality, at lower cost, and with good performance and meeting the requirements of the companies. 2. Materials and Methods 2.1. Plant Material. The samples of rosemary were harvested at the flowering stage during the month of May 2018 in the region of Fez (406 m, 34∘ 01󸀠 59󸀠󸀠 Latitude North and 5∘ 00󸀠 01󸀠󸀠 Longitude West). Only the aerial part of plant was used; the leaves and the apical parts were dried in the shade for eight days at a temperature room fixed at 25∘ C. 2.2. Microwave-Assisted Hydrodistillation. The microwaveassisted hydrodistillation was carried out using an assembly consisting of a domestic microwave oven (MWD 119 WH, whirlpool, China, 20L, 1100 W), directly connected to a Clevenger-type extractor and a cooling system to condense the distillate continuously. The excess of Condensed water was refluxed to the extraction flask in order to restore the water to the plant material (Figure 1). Microwave assisted hydrodistillation was carried out under the optimum conditions of the extracting time, microwave power, and ratio water/plant material [19]. 100 g of rosemary samples was placed in a 2-liter flask containing distilled water (200 ml), heated inside the microwave oven cavity, and the mixture was heated at a fixed power of 600 W until extraction of the all essential oils. The essential oils taken from different extractions are dried under anhydrous sodium sulphate and stored in the dark until they are used for analysis. The extractions were done at least three times and mean values of the yield and standard deviation were d (...truncated)