Riëtte de Kock is working to democratise sensory science in Africa, factoring in the food preferences and cultural traditions of the continent’s large and diverse population.
Prof Riëtte de Kock
At a sensory science conference in 2009, Riëtte de Kock felt very out of place.
“Everyone was speaking about chocolate and yoga,” she remembers. “I thought that the type of work I’m doing doesn’t fit in.”
But then, she says, a keynote speaker at the conference asked whether sensory science was only for affluent societies - exactly the question de Kock wanted to hear. That’s when, she says, “I knew what I was doing was important.”
A professor in the Department of Consumer and Food Sciences at the University of Pretoria in South Africa, de Kock has worked to develop an ambitious sensory program tailored to reflect the many foods and cultural traditions across Africa, mostly focusing on sub-Saharan Africa, and varying household economic levels.
While still a graduate student, she became aware that the sensory methods and approaches used for the rest of the world weren’t best suited to African communities. What was needed, she realised, were adaptations that would reflect the demands and preferences of those communities. She wanted to exploit sensory properties of healthy and affordable products to encourage good diets and nutrition, with a focus on Africa’s many traditional and indigenous foods.
Her reimagining of sensory methodologies is catching on. “That has become a meaningful research process and way of doing research,” she says. “The rest of the world is catching up.” She is also exploring biodiverse food sources to help food producers make appealing, nutrient-rich foods, and is working to spread sensory science across the African continent.
A world in a continent
To talk about food in Africa is to know that there are 54 countries, just over 1.5 billion people, and, by some counts, 3,000 languages, as well as many, many cultures and traditions. There are economic, literacy, and language barriers to performing sensory research, says de Kock.
South Africa alone has 11 official languages. Africa, she says, is “like a whole world in one continent.”
There are high levels of malnutrition, undernutrition, and obesity, sometimes within the same community. Recent estimates show that 20% of the total population is undernourished, food insecurity is high, and 30% of children under age five suffer from stunted growth.
In addition, many people are moving to urban centers, which has changed what and how they eat. Instead of buying locally or farming, more and more people are buying packaged and processed foods. De Kock wants to understand these new urbanites’ food choices and why they’re buying and eating what they are. “What are the motives and different considerations being used when selecting food products to eat?” she asks.
Because the typical sensory tests developed for the Global North aren’t suitable for African consumers, they need to be remodeled for use in emerging economies like South Africa. One of de Kock’s doctoral students developed a questionnaire specifically geared to African respondents, and she believes that it will contribute to better insights into how African consumers choose products, leading in turn to improved nutritional strategies.
At the University of Pretoria, de Kock’s students come from all over the continent. One student from Uganda researches the sensory qualities of sweet potatoes, one of the most important staple foods in parts of Africa. While breeders are creating new varieties that can withstand droughts and pests and are also nutritious, they don’t often consider the sensory properties of the resulting vegetable. That led to the development of varieties that people didn’t like and weren’t buying and eating. Developing new varietals and products requires reverse engineering that begins with the consumer, says de Kock.
“It takes a lot of effort and a lot of investment and time to make sure the breeding program is more successful,” she says. “They are realizing they have to bring the end user in from the start.”
The impact of urban shift
The population shift to urbanisation changes the whole dynamic of food production and choice. People are eating more sugar, fat, salt, and processed products that often lack sufficient nutrients, mirroring similar changes in the Global North. De Kock is trying to address these changes and avoid importing bad diets and bad habits. “We want to learn from that and don’t want to make the same mistakes,” she says.
Traditional diets in Africa used to be more plant based, high in fiber, and high in micronutrients, she says. The question is how to develop traditional food products that people want to buy. “You have to make traditional food products, modernize them, and make them available in urban communities,” she says.
According to the World Economic Forum, there are about 300,000 edible plants on the planet, yet we consume just 200 of them. Africa is no exception. Rice, maize, and wheat make up half the daily caloric intake for Africans.
“There are a lot of underexploited food crops in Africa,” she says. “That’s an opportunity to make more use of underutilised products.”
As with the rest of the world, climate change is changing agriculture across the African continent. It will force adaptations and a renewed look at traditional ingredients, says de Kock.
One project she is involved with is whole grain maize, a major staple in sub-Saharan Africa that is consumed in various forms, although mostly refined. While there is a tradition of having a small-scale mill at home or available within a community, urban populations rely on large-scale commercial refinement.
Whole grains have a better nutrient profile than their refined counterparts. But there are sensory challenges - stronger flavours, coarser textures, and darker colors. Whole grains also have a higher fat content and spoil more quickly, so they have a shorter shelf life. This is particularly important, de Kock explains, because school meals account for the majority of many African children’s diets, and maize meal is a major ingredient in school meals.
“This is a project close to my heart because it can have such an impact if we can improve nutritional value and develop affordable ways to stabilize maize meal to have the shelf life we desire,” she says. “That’s really exciting.”
Hely Tuorila, professor emeritus at the Department of Food and Nutrition at the University of Helsinki, has worked on several projects with de Kock at the University of Pretoria. Tuorila says that de Kock has been instrumental in building sensory science networks throughout Africa.
“She works on products that are not known to the whole world,” says Tuorila. “She has taken a leading role, which brings a lot of responsibility, and she has been very persistent.”
As part of de Kock’s goal to grow sensory research and education across Africa, in 2019 she co-created the African Network for Sensory Evaluation Research (ANSWER), which she currently chairs. The network works to bring together professionals from academia, industry, and research institutions for training and research.
“Sensory research is a young discipline in Africa,” de Kock says. “Bringing in the voice of the consumer and needs of sensory properties of products is something I’m focusing on. Sensory research has a lot to give to African communities and science communities in general.”
In 2023, her work earned de Kock the IFT Sensory & Consumer Sciences Achievement Award.
In addition to her roles at the University of Pretoria, she is the 2024–2025 president of the South African Association for Food Science & Technology.
