The proteolytic activity of Oenococcus oeni protease on the release of individual amino acids and peptides from a red wine macromolecular nitrogenous fraction was evaluated. 148.7 mg l(-1) of individual amino acids were released and a difference of 109.5 mg l(-1) with respect to the amino acids liberation from white wine was observed. Stimulatory amino acids for O. oeni growth, glutamic acid and proline, were the most important amino acids obtained by the protease activity. In the HPLC and spectral analysis of peptides before and after the protease activity of O. oeni, several changes have been observed. Three new peaks, six higher and one lower have been found in the chromatogram obtained after the enzyme action. The specific activity of O. oeni protease is higher on the red than on the white wine proteins and this is important considering the lower protein concentration in red wine. (C) 1999 Federation of European Microbiological Societies. Published by Elsevier Science B.V. All rights reserved.

This work was carried out in the framework of the Iberoamerican Cooperation Program from the Spanish Ministerio de Educación y Cultura. The authors thank the ¢nancial support given by CIUNT and CONICET, Argentina and the Comisión Interministerial de Ciencia y Tecnología (Project ALI97-0630)España.

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