1. Matforsk, Norwegian Food Research Institute, Osloveien 1, N-1430 Ås, Norway; Deptartment of Food Storage and Technology, Faculty of Food Sciences, Agricultural University of Wroclaw, ul. C. K. Norwida 25, 50-375 Wroclaw, Poland; and Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, P.O. Box 5003, N-1432 Ås, Norway