Sweet potatoes are not only delicious but also one of the top-yielding crops in terms of calories per hectare. Calories alone, though, aren’t enough, and some sweet potatoes pack a bigger nutritional punch than others.
Bernadetha Kimata, a senior agricultural research officer at the Tanzania Agriculture Research Institute, is working hard to see the orange-fleshed variety of sweet potato win over the hearts and minds of the farmers and consumers in her country. As she explained to Grow Further in an interview, getting more people to eat orange-fleshed sweet potatoes could help solve a host of problems linked to malnutrition, in particular vitamin A deficiency which can cause children to go blind.
“Orange-fleshed sweet potato is not commonly consumed in Tanzania or elsewhere in the region because people have been growing local sweet potato varieties that are locally consumed for a long period of time,” Kimata told us. “These varieties are low in beta carotene, but higher in dry matter content.”
In other words, the more commonly consumed sweet potato varieties may boast high fiber content, but they’re lacking in other nutritional qualities important for health, in particular for children’s health, Kimata explained. “Orange-fleshed sweet potatoes should be consumed more because they are bio-fortified with beta carotene, a plant-based compound that is converted to vitamin A in our bodies,” she said. “Apart from vitamin A, they are rich sources of vitamins and minerals such as B, C, K, and phosphorous and potassium.”
Not only that, “they boost the immune system of the body and prevent vitamin A deficiency in children below five years,” she added.
In short, the orange-fleshed sweet potato is a superfood, a potent ally in the fight against malnutrition. Getting people to eat more orange-fleshed sweet potatoes, however, is proving to be something of a challenge, Kimata admitted. “Since orange-fleshed sweet potato boiled roots are low in dry matter but higher in beta carotene content, people do not like the boiled roots.” In other words, consumers are having a hard time adapting these root vegetables to their local cuisines and food customs.
Step one: more biofortification
Bernadetha Kimata and her research colleagues came to Grow Further’s attention during our first grant announcement. As the research team lead, Kimata kindly took time out of her busy schedule to explain her work and why the orange-fleshed sweet potato deserves a better market.
Kimata said the orange-fleshed sweet potato is starting to attract more interest from Tanzania’s smallholder farmers, but winning over the food-purchasing public in her country is an ongoing challenge. She and her research partners at the Tanzania Agriculture Research Institute (TARI) think they have one possible solution: processed foods from vitamin and nutrient-rich orange-fleshed sweet potatoes.
“Research studies have found that people like orange-fleshed sweet potato value-added products like crisps, biscuits, muffins, pancakes, jam, juice, puree, concentrate, and weaning mix more than boiled roots,” Kimata said. Thus, her focus is on expanding orange-fleshed sweet potato farming while further increasing the crop’s appeal through developing new processed food products.
The very first step, however, is to develop better bio-fortified varieties of orange-fleshed sweet potatoes that can be readily cultivated in the climates and regions found in Tanzania. We wish to evaluate and release the genotypes to suit all sweet potatoes-producing zones in the country,” Kimata said, “hence, increased consumption and adaptability for improved nutritional status of the community and the country at large.” She said her team is first working on producing specialized bio-fortified orange-fleshed sweet potatoes in TARI’s Ukiriguru region. They’re also exploring ways to improve sweet potato varieties “with low dry matter to high dry matter content.”
“Research studies have found that people like orange-fleshed sweet potato value-added products.”
Step two: processed foods, the good kinds
The next step will be to develop new processed food products that use orange-fleshed sweet potatoes in the production process. Kimata believes this will prove to be the most critical part of her team’s work.
“This is a very serious part of our research, as we want to combat vitamin A deficiency among vulnerable groups in Tanzania,” Kimata stressed. They plan to develop new product recipes and adapt existing recipes to use orange-fleshed sweet potatoes. This will involve a trial-and-error process to develop orange-fleshed sweet potato-based products that are appealing to consumers.
There is plenty of fieldwork ahead, as well, Kimata stressed.
Their plan also involves exploring and developing efficient and effective orange-fleshed sweet potato harvesting, transportation, packaging, and storage methods in a search for the most effective ways to commercialize this superfood up and down the value chain. “The quality control of production, harvesting, transport, processing, packaging, storage, and marketing will be considered and taken care of,” she said.
Promising signs
Kimata acknowledges that she has a long road ahead of her, but signs are pointing in the right direction.
It helps that farmers in Tanzania are increasingly interested in growing orange-fleshed sweet potatoes. They appear to be catching on to the fact that the roots and vines that grow with these sweet potatoes can also be processed and sold in food markets, creating more income-generating opportunities. Kimata hopes momentum like this will help carry her mission forward.
“The orange-fleshed sweet potato value chain has lots of opportunities,” Kimata said.
— Grow Further
Photo credit: A farmer shows off part of her sweet potato crop (left); Bernadetha Kimata examines sweet potatoes during harvest (right). Bernadetha Kimata.
