1. Department of Food Science, Stellenbosch University, Private Bag X1, Matieland (Stellenbosch), 7602, South Africa.
2. Corresponding author. Phone: +27 21 808 3511. Fax: +27 21 808 3510. E-mail: mman@sun.ac.za
3. Current address: Department of Bioengineering, Temple University, Philadelphia, PA 19122, U.S.A.
4. Department of Genetics, Stellenbosch University, Private Bag X1, Matieland (Stellenbosch), 7602, South Africa.
5. Current address: Queensland Alliance for Agriculture and Food Innovation Institute, The University of Queensland, St. Lucia, Queensland 4072, Australia.