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How is castor oil obtained?

How is castor oil obtained?

Castor oil is a non-edible oil that has been used in numerous sectors for thousands of years (medicine, automotive, cosmetics...). In ancient Egypt, people used it as fuel to light lamps, but also as a natural remedy to stimulate labor before childbirth. Today, it is found in a plethora of skin and hair care products, mainly for its soothing and strengthening properties. Let's delve into its extraction process.

Summary
Published February 14, 2024, by Maylis, Chemical Engineer — 3 min read

Castor Oil: What is it?

Castor oil is an ingredient obtained after processing the seeds of Ricinus communis. This shrub is part of the Euphorbiaceae family. It is cultivated in India, China, Brazil, and East Africa. Also known as "castor oil," this vegetable oil has a fairly viscous oily texture and is not edible. It lends itself to skin or hair application, allowing it to be adopted in the formulation of care for the skin, nails, hair, eyelashes, or eyebrows. Castor oil contains, among other things, fatty acids, including ricinoleic fatty acid or linoleic fatty acid. However, its composition can vary depending on several factors, including cultivation conditions and the cultivar. In terms of virtues, castor oil has nourishing, strengthening, stimulating, healing, and calming properties.

How is castor oil obtained?

Castor seeds contain 30 to 50% oil (m/m). Castor oil can be extracted from castor seeds through mechanical pressing, solvent extraction, or a combination of pressing and extraction. At Typology, the castor oil is derived solely from the first cold pressing of the seeds; no solvent is used. The extraction process unfolds as follows:

  1. The shells of the Ricinus communis are harvested and cleaned before being shelled to extract the seeds;

  2. The seeds are ground and pressed using an endless screw press. Although this process can be done at low temperatures, mechanical pressing only results in a recovery of about 45% of the oil from castor seeds. Higher temperatures can increase the efficiency of extraction. Yields of up to 80% of the available oil can be achieved using high-temperature hydraulic pressing in the extraction process.

  3. In order to separate the oil from the hydrophilic compounds, centrifugations are performed. We then obtain raw castor oil.

  4. During the refining process, impurities such as colloidal matter, phospholipids, excess free fatty acids (FFA), and coloring agents are removed from the oil. The removal of these impurities prevents the oil from deteriorating during extended storage. The steps in the refining process include degassing, neutralization with a strong base like sodium hydroxide, bleaching, and deodorization.

Following these steps, castor oil is safe and can be adopted in cosmetology. Indeed, it is rid of a toxic enzyme initially present in the seeds called ricin. It is this toxin that prevents the use of this plant for food purposes.

Source:

  • Vinay R. Patel & al., Castor Oil: Properties, Uses, and Optimization of Processing Parameters in Commercial Production, Lipid Insights. (2016).

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