2.2.4.3. Microwave assisted extraction under pressure (vapor pressure)
Rosemary leaves were packaged in gauze in order to be totally immersed in the solvent, and placed in a closed Teflon reactor. The whole was introduced in a MW reactor (1 kW, Ethos 1, Milestone, Italy) and heated using microwave until the fixed temperature. Extraction was done at 125 °C and at 150 °C during 30 min. Microwave power was fixed at 300 W but it varied depending on temperature, firstly to reach the set temperature and then to keep it constant during the extraction step. Temperature and pressure were measured with external sensors. Each experiment was performed in triplicate.