Castor Oil Extraction: Methods and Impacts

This paper provides an overview of castor (Ricinus communis L.) plant characteristics, cultivation, seed harvest, reception, and pretreatment, and oil extraction, refinement, storage, and physicochemical properties, composition, and uses. It focuses on various traditional and novel methods of castor oil extraction and their optimization, kinetics, thermodynamics, and techno-economic, environmental, and social issues. Generally, novel techniques proved higher oil yield in a shorter time than conventional ones. The hybrid ultrasound-microwave-assisted extraction provided the highest oil yield, whereas supercritical CO2 extraction showed no effect. The composition and properties of castor oil depend on not only extraction methods but also geographical origin, climate, soil, cultivar, and harvest time. The future perspective involves utilizing the entire biomass in a biorefinery to maximize the value of oil, seed cake, and waste residues. Castor oil production offers opportunities for sustainable development, but challenges must be addressed to ensure sustainability and social responsibility throughout the production process.