The castor oil plant, Ricinus communis, is a species of flowering plant in the spurge family, Euphorbiaceae, Castor seed is the source of castor oil, which has a wide variety of uses. The seeds contain between 40% and 60% oil that is rich in triglycerides, mainly ricinolein.

Gujarat is the highest castor seeds growing state in India contributing 90% of total indigenous production. The season for castor seed is considered from December to March and arrival is continuing up to May. The processing is continuing up to May or Mid-June, i.e., approximately 260 days in a year. Based on capacity of 55 tons per day, the processor needs approximate 14,300 MT of castor seeds per annum which is abundantly available in Gujarat and other states like Rajasthan, Andhra Pradesh, and Telangana.

Following is the GROUNDNUT / CASTOR / MUSTARD oil extraction process:

Storage → Cleaning → Dehulling → grinding or rolling → Heating → Pressing → Refining → Packaging.

Castor oil can be extracted from castor beans by mechanical pressing, solvent extraction, or a combination of pressing and extraction. After harvesting, the seeds are allowed to dry so that the seed hull will split open, releasing the seed inside. The extraction process begins with the removal of the hull from the seeds. This can be accomplished mechanically with the aid of a castor bean de-huller or manually with the hands. When economically feasible, the use of a machine to aid in the de-hulling process is more preferable. After the hull is removed from the seed, the seeds are then cleaned to remove any foreign materials such as sticks, stems, leaves, sand, or dirt. These materials can usually be removed using a series of revolving screens or reels. Magnets used above the conveyer belts can remove iron. The seeds can then be heated to harden the interior of the seeds for extraction. In this process, the seeds are warmed in a steam-jacketed press to remove moisture, and this hardening process will aid in extraction. The cooked seeds are then dried before the extraction process begins. A continuous screw or hydraulic press is used to crush the castor oil seeds to facilitate removal of the oil. The first part of this extraction phase is called prepressing. Prepressing usually involves using a screw press called an oil expeller. The oil expeller is a high-pressure continuous screw press to extract the oil.