1. Department of Chemistry, University of Sassari, Via Vienna 2, 07100 Sassari, Italy, Fax: +39‐079‐229559
2. Institute of General Food Chemistry, Technical University of Lodz, ul. Stefanowskiego 4/10, 90924 Lodz, Poland
3. Istituto C.N.R. di Chimica Biomolecolare, Trav. La Crucca 3, 07040 Li Punti, Sassari, Italy