An idea that could eventually help shrink the pomegranate industry’s plastics footprint and can curb food losses along its value chain. That’s what a newly graduated PhD student in Horticultural Sciences at Stellenbosch University (SU)in South Africa, Dr Tatenda Kawhena, came up with when he developed an edible coating that extends the storage and shelf life of this Mediterranean fruit.
Dr Tatenda Kawhena
The coating includes ingredients such as gum Arabic, maize starch, lemongrass essential oil, glycerol and an emulsifier. Gum Arabic, a natural gum, consists of the hardened sap of two species of Acacia tree, Senegalia senegal and Vachellia seyal, which are not indigenous to South Africa.
Through laboratory-based studies, Dr Kawhena showed proof of concept that dipping ‘Wonderful’ pomegranates into the solution he developed works well to extend the storage and shelf life of the fruit. Furthermore, the fruits last even longer when they are first dipped into the coating solution, and then packaged in plastic polyliners and standard open cartons.
Left: Treated pomegranates Right: untreated pomegranates
A next step would be to test it within the context of a packhouse. There has been a rapid rise in pomegranate production in South Africa to meet global demand. However, pomegranate fruit is highly susceptible to postharvest losses and waste, which limits the growth of the local industry.
“Great care must be taken to ensure that pomegranates last as long as possible, and do not go to waste once they have been picked. They are easily damaged along the postharvest logistics chain. Therefore, the development and application of new science-based technologies to reduce postharvest losses in pomegranate fruit is a priority. Currently, as part of efforts to make pomegranates being exported last longer, around ten fruit are packed together into a plastic bag, and then further, into cartons…Within one fruit season, that all adds up to a lot of plastic, which is often only used once,” explains Dr Kawhena.
His PhD studies were funded by the Pomegranate Producers’ Association of South Africa (POMESA) and the DSI-NRF South African Research Chairs Initiative (SARChI) in Postharvest Technology at SU. His studies were supervised by Prof Umezuruike Linus Opara, the South African Research Chair (SARChI) in Postharvest Technology, a distinguished professor in the SU Department of Horticultural Science, and a world leader in postharvest care of pomegranates and Prof Olaniyi Fawole of the University of Johannesburg.
Path towards a PhD
Dr Kawhena hails from Marondera in Zimbabwe, and matriculated in 2009. Some of his results have already been published in peer-reviewed scientific journals.
Dr Kawhena is now pursuing a career in the South African horticultural sector, as a Project Manager for a company based in Paarl focusing on the independent evaluation of new fruit cultivars and rootstocks.
For more information:
Dr Tatenda Kawhena
Faculty of AgriSciences, Stellenbosch University
Tel +27 79 142 9373
Email: [email protected]
www.agric.sun.ac.za