Knowledge for a sustainable world

Joshua Muhumuza

Jacinta Nyaika is a third year PhD student in the Food and Markets Department at NRI. She took five minutes out her day to talk to us about her research on an important food security crop, life at NRI and her future plans. 

Early education in Malawi

Originally from Malawi, Jacinta is an agronomist with a BSc and MSc in Horticulture from the University of Malawi (Bunda College of Agriculture). After completing her bachelor’s degree in 2009, she was awarded a scholarship by South Africa’s Department of Science and Technology to study for her master’s degree. Shortly after her master’s, Jacinta joined Lilongwe University of Agriculture and Natural Resources (LUANAR) as a lecturer in Postharvest Technology for Horticultural Crops. To date, she remains an active researcher in the Department of Horticulture. In 2019, she won a Commonwealth scholarship to pursue her PhD. However, due to COVID restrictions on travel, Jacinta’s enrolment at NRI was delayed until 2021.

Quest to make cassava safer

Jacinta’s research is focused on food safety issues associated with the production and postharvest handling of cassava, a staple for over 800 million people in sub-Saharan Africa (SSA).

Cassava flourEasy to grow in poor soils and resilient to drought, cassava is a major and cheap source of food for millions of people worldwide. Yet despite its broad significance to food security, cassava can be risky if not properly prepared. Cassava contains cyanogenic glycosides which are plant chemicals that are converted by enzymes to highly toxic hydrogen cyanide, usually following damage/injury to a plant, for example, through processing or eating. Ingesting high levels of cyanide can cause nausea, vomiting, dizziness, convulsions and even death. Cassava therefore must be properly handled postharvest to reduce the risk of cyanide poisoning. In Malawi, some communities ferment bitter cassava varieties into products like Kondowole and Viphumu to remove cyanide.

Jacinta is examining the pre- and post-harvest factors influencing cyanogenesis (production of hydrogen cyanide from cyanogenic glycosides), as well as safety and quality of cassava products in SSA. Her research recognises that food safety issues mainly arise from the point of production and run through the whole food value chain. Her findings will provide recommendations for adaptation and mitigation in Malawi.

During her time at NRI, Jacinta has acquired multiple skills including setting up and running field and greenhouse experiments, studying enzyme activity leading to cyanogenesis in cassava and analysing food safety hazards during cassava processing. ‘The skills I have attained will help me in my profession as I advance into research’, she said.

‘I like that NRI has a pool of expertise and resources I can tap as a PhD research student. More importantly, I look forward to the collaborations that will be established after my studies, primarily since NRI research focuses on my research area’, she added.

Research highlights

Cassava plantEarly results from her work show that cassava toxicity can still be a challenge due to several factors. First, climate variation results in seasonal droughts associated with rising cyanide levels due to concentration effects in the roots. Second is farmers’ willingness to adopt low cyanide cassava varieties which is influenced by cultural traditions in the preparation and utilisation of cassava. Further, Jacinta’s field experiments in Malawi showed that soil fertility influences cyanide development in cassava roots. Screening of processed cassava products from different regions in Malawi revealed high residual cyanide and high microbial hazards in traditional unfermented products compared to fermented ones.

‘These results are essential to African nations, especially since cassava is a significant staple widely promoted as an adaptation and mitigation measure against climate change. With rising fertiliser prices making production of other crops unaffordable for smallholder farmers, there is a need for innovative measures to maintain soil fertility and ensure availability of safe food to local African consumers’, Jacinta advised.

Driven by rural beginnings

Jacinta’s inspiration for her work comes from her mentors and childhood experiences growing up in rural Malawi where people lacked basic necessities and having enough food was a luxury. ‘I have worked with people who have believed in me, that I can help change the world in our unique way within the local [Malawian] context’, she reflected. A story from her grandmother encapsulates Jacinta’s motivation. She briefly retold it: ‘At a very young age, in a tale, my grandmother taught me that we can only have enough food if we know how to pick every grain that has fallen during winnowing and take care of it. I later translated that advice into developing and promoting scientific technologies that ensure that harvested food is not lost.’

Her advice to current and prospective students: ‘Look where you come from and yearn to be a change maker to the local problems there.’

Inspiring change in Malawi and beyond

Upon completion of her studies, Jacinta plans to return to Malawi where she will engage in and promote research and innovative technologies to ensure safe food is achieved locally. She believes a nation can only be healthy and productive if the citizens have access to safe, nutritious food. However, Jacinta’s broader objectives stretch beyond Malawi. ‘My long-term goal is to establish a centre for postharvest technology and safety of local food value chains in SSA that are well adapted to our environment and well accepted by the local consumers,’ she revealed.