1. Department of Food Science and Technology, Makerere University, PO Box 7062, Kampala, Uganda.
2. Department of Food Science, University of Pretoria, Pretoria 0002, South Africa.
3. Food Science and Technology Programme, CSIR Bio/Chemtek, PO Box 395, Pretoria 0001, South Africa.
4. Corresponding author. Phone: +27 12 420 4296. Fax: +27 12 420 2839. E-mail:jtaylor@postino.up.ac.za