1. Department
of Food and Environmental Sciences, University of Helsinki, P.O. Box
27, FI−00014 Helsinki, Finland
2. Dipartimento
di Scienze del Suolo, della Pianta e degli Alimenti, University of Bari, Via G. Amendola 165/a, Bari 70126, Italy
3. VTT Technical Research Centre of Finland, P.O. Box 1000, FI-02044 VTT Espoo, Finland