1. Horticulture and Crop Protection Division, Agricultural Research Council Tropical and Subtropical Crops, Mbombela, South Africa
2. Department of Dietetics and Human Nutrition, School of Agricultural, Earth and Environmental Sciences, University of KwaZulu-Natal, Pietermaritzburg, South Africa
3. Laboratory for Microscopy and Microanalysis, University of Pretoria, Pretoria, South Africa
4. Postharvest Technology Division, School of Agricultural Sciences, Faculty of Agricultural and Natural Sciences, University of Mpumalanga, Nelspruit, South Africa
5. Department of Biotechnology and Food Technology, University of Johannesburg, Johannesburg, South Africa
6. Department of Botany and Plant Biotechnology, University of Johannesburg, Johannesburg, South Africa