1. Department of Food Science, University of Stellenbosch, Private Bag X1, 7602 Matieland (Stellenbosch), South Africa; Post-harvest and Wine Technology Division, ARC Infruitec-Nietvoorbij (The Fruit, Vine and Wine Institute of the Agricultural Research Council), Private Bag X5026, 7599 Stellenbosch, South Africa; and PROMEC Unit, Medical Research Council, P.O. Box 19070, 7505 Tygerberg, South Africa