*2.3.1.1.5 Cool pressing method*

Also kwon as scarification method, this is one of the best methods to extract EOs. The term cool pressed theoretically means that the oil is expeller-pressed at low temperature and pressure. This process insures that the resulting oil is 100% pure and retains all the properties of the plant. Here the heat is reduced and minimized throughout the batching of the raw material. EOs are then separated from the material by centrifugation [36].

Since economy, competitiveness, eco-friendly, sustainability, operation costs, high efficiency, and good quality become keywords of the modern industrial production, the development of EO extraction techniques has never been interrupted. The most relevant disadvantage of conventional techniques are time and solvent consumption and also related to the thermolability of EOs components which undergo chemical alteration (hydrolyze, isomerization, oxidation) due to the high

**Figure 4.** *Soxhlet equipment [35].*

applied temperatures [37]. The quality of the obtained oil is damaged, particularly if the extraction time is long. It is important that the extraction method maintain the chemical composition and the natural proportion at its original state. Strictly speaking, conventional methods are not the only way for the removal of EOs. Novel techniques known as innovative have been developed for this purpose but may not necessarily be widely used for commercial production due to the high cost of production of oils without any alteration of their thermosensitive components (**Figure 5**).
