1. Department of Agricultural and Biosystems Engineering, University of Kassel, Nordbahnhoftstraße 1a, 37213 Witzenhausen, Germany
2. Natural Resources Institute, University of Greenwich, Central Avenue, Chatham Maritime, Kent ME4 4TB, UK
3. Ecole Supérieure d’Agronomie, Université de Lomé, Lomé BP 1515, Togo
4. Department of Consumer and Food Sciences, University of Pretoria, Private Bag X20, Hatfield 0028, South Africa