Mechanical expression is used for extracting essential oils from the rinds of Citrus fruits such as lemons, bergamot, oranges and limes. Expression is generally preferred for Citrus oils since their components in aldehyde structure can be easily decomposed in heat application. Essential oils are found in the secretory glands of Citrus peels. In order to extract essential oils from these glands, the whole fruits or their peals move in a system covered with thousands of sharp and tiny spikes. As this process occurs, small glands break open and release their contents. Fruits or peals are washed with water to collect these essential oils. To isolate essential oil from this mixture, it is filtered and centrifuged to allow obtaining pure essential oil. Mechanical expression provides high quality products with characteristic fragrances nearly identical to the starting fruit. Citrus essential oils can also be obtained by hydrodistillation. However, distilled Citrus essential oils are considered to be low quality and are not preferred to use in aromatherapy due to structural changes.

• Essential oils obtained by mechanical expression may contain furanocoumarins which is responsible for the phototoxic effect of Citrus For this reason, in order to avoid the risks associated with phototoxicity, after using Citrus oils such as lemon, bergamot and grapefruit topically, Tisserand &Young recommend waiting 12 hours before exposing yourself to sun. Since there are no furanocoumarins in Citrus oils obtained by steam distillation, steam distilled essential oils are not show phototoxic effects.
• Although mechanical expression is sometimes called “cold-pressing”, it should not be confused with the production method of fixed oil from seeds or fruits.
• In the product information of Orlife essential oils, origin and the production method are stated in detail. It is important to check this information during the choosing of your essential oils.

References

Başer, K.H.C., Buchbauer, G., 2015. Handbook of Essential Oils: Science, Technology, and Applications, Second ed. CRC Press, Boca Raton, FL.

Buckle, J., 2015. Clinical aromatherapy – Essential Oils in Healthcare, Third ed. Elsevier Health Sciences,  London, UK.

Tisserand, R., Young, R., 2013. Essential Oil Safety: A Guide for Health Care Professionals. Elsevier Health Sciences, London, UK.