TECHNOLOGY FOCUS - ORGANIC CHEMISTRY - Preferred Process: The step (c) comprises chemical transesterification of a phase containing glycerides of ricinoleic acid and alcohol in the presence of a basic catalyst to obtain fraction C rich in ricinoleic acid esters. The step (c) comprises a second enzymatic transesterification reaction performed in the presence of a lightweight alcohol and a lipase, where the lipase is: lipases derived from Candida antarctica B (preferably Novozyme 435 (RTM: Lipase) in the immobilized form), Rhizomucor miehei (preferably Novozyme RM IM (RTM: Lipase) in the immobilized form), Thermomyces lanuginosa (preferably Novozyme TL IM (RTM: Lipase) in the immobilized form), Pseudomonas cepacia, Aspergillus Niger, Rhizopus oryzae, Rhizopus arrhizus, Candida rugosa or Mucor javanicus, porcine pancreatic lipase or other lipase leading to the formation of fraction C enriched with ester ricinoleic acid. The lipase extracted from Geotrichum candidum is typoselectively used in steps (a) and/or (c), where the lipase is immobilized on an inorganic support (e.g. of Celite (RTM: Diatomaceous earth), silica or alumina type) or an organic support of cellulosic nature (e.g. of Sephadex (RTM: Crosslinked dextran gel) or diethylaminoethyl cellulose type) or a synthetic polymer (e.g. of Lewatit (RTM: Ion exchange resin), Dowex (RTM: Ion exchange resin), Amberlite (RTM: Ion exchange resin), Accurel (RTM: Polypropylene support) type). The step (a) is performed for at most 1 hour, preferably not more than 30 minutes. The ratio of lipase/substrate in step (a) is at least 0.5% part/part (p/p). The ratio of substrate/alcohol in step (a) is 1: 4.5-1: 0.75, where the alcohol is added one or more times. Preferred Components: The lightweight alcohol is a lower aliphatic alcohol comprising methanol (preferred), ethanol, isopropanol or n-propanol. EXAMPLE - Methanolysis of castor oil was carried out at 30 degrees C, and atmospheric pressure in the presence of molecular sieves (3A, 0 2 mm) at higher than 10% of the substrate (castor oil). The ratio of protein concentrate of typoselective lipase from G. candidum to substrate was 1.5% part/part and the molar ratio of methanol to castor oil triglyceride was 4.5:1 in three successive additions for 0, 2 and 4 hours of reactions. The whole reaction medium was homogenized by a vortex (10 s). The thin layer chromatography separation was performed by depositing on glass plates pre-coated with silica (100 x 200 mm) for 10 mg/ml of sample dissolved in a mixture of acetone and acetonitrile (50/50 v / v). After elution with a mobile phase constituted of hexane/diethyl ether/acetic acid (40:60:1 v / v), the species present were revealed by spraying with a solution of saturated copper sulfate and phosphoric acid (50:50 v / v) and incubated for 10 minutes at 180 degrees C. The products obtained during the transesterification in the presence of methanol were essentially the ricinoleic acid, linoleic acid, oleic acid and the corresponding methyl esters comprising methyl ricinoleate, methyl linoleate and oleate methyl oleate.