In this work, a study about the effect of various operational conditions on the quantity of oil and soluble solids capable of being extracted from rosa mosqueta rosehip seeds is undertaken. Both the particle sizes assayed (<= 0.6 mm, 0.6-1 mm, and 1-2 mm) and the solvent-to-solid ratios (15:1, 25:1, and 50:1) showed a remarkable influence on the extraction efficiency. Extracted substances obtained by using the minor particle size or the maximum solvent-to-solid ratio doubled, at least, those attained by working under any other conditions. A major weight of kinetics upon equilibrium factors can be inferred from the short extraction times and high effective diffusivity values (being the lower one 1.97 x 10(-11) m(2) s(-1)) assessed for any condition. The antioxidant power of extracts was evaluated by ability to scavenge the DPPH radical. Results noteworthy depended on the solvent used to extract; whilst an similar to 80% DPPH inhibition percentage was reached in ethanol extracts, values of 52.2% or 41% were found in methanol and aqueous extracts, respectively. Even so, antioxidant capacity of Rosa rubiginosa extracts was much higher than that reported for other agricultural matrixes. (C) 2006 Elsevier Ltd. All rights reserved.