The effect of reaction conditions on the extent of conversion in hydrolysis of blackcurrant oil was investigated. The enzyme used was Lipozyme, a lipase from Mucor miehei immobilised on macroporous anionic resin. The reaction was carried out in a continuous flow reactor at 10-28 MPa and 30-50degreesC with carbon dioxide saturated with oil and water (55-100%) flowing up through the enzyme bed. Analysis of product composition indicated unfavourable hydrodynamics with significant mixing in the reactor when solvent interstitial velocity was lower than 4 cm min(-1), while above this velocity value the flow pattern was near to plug flow. Lipase stability was very good with no activity reduction observed during a long-term experiment. The reaction rate was a function of the ratio of enzyme load to solvent volumetric flow rate. A complete hydrolysis of oil was achieved in the experiments carried out with the enzyme load of 0.8 g and CO2 flow rate of 0.4-0.9 g min(-1). The effects of pressure (10-25 MPa) and temperature (30-40degreesC) on the reaction rate were small, and the effects Of CO2 saturation with water and of enzyme distribution in the reactor were negligible. Lipozyme displayed specificity towards linolenic acids; the release of alpha-linolenic acid was faster and that of gamma-linolenic acid slower than the release of other constituent acids present in blackcurrant oil. (C) 2003 Elsevier Science Ltd. All rights reserved.