1. Department of Ecology and Natural Resources Management, Norwegian University of Life Sciences, P.O. Box 5003, NO-1432 Ås, Norway.
2. Department of Forest Products and Markets, Swedish University of Agricultural Sciences, P.O. Box 7060, S-750 07 Uppsala, Sweden.
3. Norwegian Food Research Institute, Osloveien 1, NO-1430 Ås, Norway.
4. Department of Chemistry, Biotechnology and Food Science, Norwegian University of Life Sciences, NO-1430 Ås, Norway.