Meet Stellenbosch University’s two pomegranate PhDs

Dr Ebrahiema Arendse and Dr Zinash Assefa Belay. Picture: Engela Duvenage

Ebrahiema Arendse from Surrey Estate in Athlone first went to nursing college after school, before taking part-time evening classes to improve his matric marks and to gain university access. Not even a car accident in 2014 and having difficulty walking since then has kept him from pursuing his dream to become a scientist.

Chemical engineer and food scientist Zinash Assefa Belay hails from Ethiopia’s capital where she was a lecturer and head of department at Addis Ababa Science and Technology University.

Although the duo come from vastly different places on the African continent, they have two things in common. They both received a PhD in Food Science from Stellenbosch University’s Faculty of AgriSciences in December. And both did their research on pomegranates.

One of their fellow students and research compatriots, Karen Munhuweyi, was also scheduled to formally receive her PhD – also for work related to pomegranates – in December. She was, however, late into her second pregnancy. On doctor’s orders she decided not to travel from Johannesburg to Stellenbosch for the graduation ceremony, but to defer receiving her own doctorate until March.

Theirs would otherwise have been the largest group of students so far to simultaneously receive PhDs from Stellenbosch University for work about this so-called “super fruit”. Pomegranates are becoming increasingly popular worldwide because of the health benefits and aesthetics attached to them.

The three students each worked on different aspects of the fruit’s quality, packaging and shelf life.

Dr Arendse adapted existing scanning techniques into a non-destructive quality control method for pomegranates.

Dr Belay established the optimal temperature conditions, gas combinations and the type of packaging film material that maintains the quality and shelf life of pomegranate arils.

Dr Munhuweyi developed a method to trap essential oils like cinnamon into a fume, which then could provide the fruit with a protective layer against fungi like Botrytis that often cause decay and rot. This leads to post harvest losses and reduced profitability.

Their work forms part of the endeavours of the DST-NRF South African Research Chair in Postharvest Technology in the SU Department of Horticultural Science. Under leadership of agricultural engineer Professor Umezuruike Linus Opara, scholars and students have over the past eight years established the best ways to handle and market pomegranates once these fruits are harvested. They have among others established protocols for when varieties such as “Wonderful”, “Acco” and “Herskowitz” should be harvested, what the best packaging materials and methods are, what the optimum storage conditions should be and testing ways to increase shelf life.

“South Africa competes with countries such as Chile and Argentina to supply in the off-season demand for pomegranates for consumers in the Northern Hemisphere,” says Professor Opara, who is recognised globally as the leading researcher on pomegranate-related postharvest technology. “If we can provide excellent science, we can help our producers gain an edge.”

Professor Opara and his multi-disciplinary research team have already contributed a wealth of knowledge about best practices to South Africa’s emerging pomegranate industry. Over the past six years 20 MSc students and 14 PhD students from a variety of interdisciplinary fields have graduated – from food science to engineering and horticulture. These efforts are not only funded through the Department of Science and Technology’s South African Research Chair Initiative, but also through the Postharvest Innovation Fund, the Pomegranate Growers’ Association of South Africa (POMASA), the Perishable Products’ Export Control Board and Biogold International (Ltd).

Just because the newly graduated PhDs’ work was about fruit doesn’t mean that it is frivolous or was easy to do. Their supervisors expected the highest possible standards from them, and also that as many findings and suggestions as possible are published to the benefit of the scientific community and the industry alike.

Dr Arendse and Dr Assefa recall many late nights and early mornings in the laboratory, to ensure that their experiments are completed timeously and properly, and that all the necessary readings and data are gathered so that they can substantiate their suggestions to industry with good science.

“There are a few blankets and pillows in one of the offices, in case you have to sleep over while you wait for your experiments to be completed,” Dr Arendse says. “It has happened quite often.”

Working with pomegranates can also be more labour-intensive than is probably the case with many other fruits. First there is the challenge of opening the fruit and extracting the arils so that these can be examined.

“Even when you get the hang of it, it can still take a minimum of 20 minutes to release all the arils from one fruit,” says Dr Arendse.

“And it can cause quite a skin irritation,” adds Dr Belay.

“We have spoilt many white lab coats during our studies,” says Dr Arendse. “The juice doesn’t wash out easily, and stains the material.”

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