1. Nutrition and Bromatology Group, Department of Analytical and Food Chemistry, Food Science and Technology Faculty; University of Vigo-Ourense Campus; 32004 Ourense Spain
2. Sustainable Forest Management Unit, Department of Soil Science and Agricultural Chemistry; University of Santiago de Compostela-Lugo Campus; 27002 Lugo Spain
3. Forest Research Centre Lourizán; Consellería de Medio Rural, Xunta de Galicia PO Box 127. 36080 Pontevedra Spain