Extraction of Chamomile (Matricaria recutita L.) essential oil using the green technology of Microwave free-solvent extraction

The essentials oils are important in food industry, mainly for flavors and bioactive compounds. In the last years, new techniques for the extraction of essential oil has been developed aiming to improve yields, among them, the green technology of microwave solvent-free extraction (ME). This study aimed to assess the benefits of this method on the Chamomile (Matricaria recutita L.) essential oil quality and yield compared to the extraction by steam distillation (SD). The oil obtained by ME and SD presented a blue color, a solubility in 70% ethanol (v/v) of 4, a relative density of 0.929-0.925g/ml, a refractive index of 1.5013-1.4790, and an acidity index of 6.23 and 3.43 respectively. The yields were significantly different between extraction methods, being the highest 0.5ml (0.083% v/w) for ME and 0.2ml (0.03%) for SD. The GC-MS analysis of chamomile essential oils obtained showed a markedly difference in its principal components such as Chamazulene, α-Bisabolol, α-Bisabolol oxide A and α-Bisabolol oxide B. The ME had a 97% and 20% more content of Chamazulene and α-Bisabolol respectively, whilst SD an 88% and 12% more content of α-Bisabolol oxide A and B respectively. Considering that Chamazulene content is strongly related to price and α-Bisabolol has been associated to the anti-inflammatory properties of Chamomile, the results suggest that ME is an outstanding alternative for essential oil extraction due to much higher yield and quality compared to the steam distillation.