1. Sør‐Trøndelag University College, Faculty of Food Science and Medical Technology, 7004 Trondheim, Norway;
2. Plantebiosenteret, Department of Biology, Norwegian University of Science and Technology, 7491 Trondheim, Norway;
3. Department of Viticulture and Enology, University of California, Davis, CA 95616, USA;
4. Skogforsk, Department of Ecology and Environment, 1432 Ås, Norway