Sweetpotato puree makes nutritious, inexpensive bread while creating a new market for farmers

 

By Michael Friedmann, RTB Science Officer

At the Organi Ltd factory, in Western Province, Kenya, a grinder was churning out ribbons of an orangey puree, which workers quickly wrapped and sealed in plastic bags under vacuum.  I was tempted to stick my finger in and grab some, as it looked quite tasty, but we were covered in protective clothing so as not to contaminate the product. No fingers allowed! 

I was visiting the factory with Tawanda Muzhingi and Penina Muoki, research scientists with the International Potato Center (CIP) who had taken the time to show me the value chain for orange-fleshed sweetpotato (OFSP) in Western Kenya.  A CIP-led project has been promoting the development of products made from OFSP to create and expand markets for sweetpotato root producers, and the vine growers who provide them with planting material. 

All this as part of an effort to combat Vitamin A deficiency (VAD) a critical health problem in sub-Saharan Africa (SSA) that can lead to blindness and stunting in young children.  Campaigns to encourage the production and consumption of OFSP by smallholder families have been shown to be an effective way to combat VAD.  However, people in Africa have traditionally eaten white or yellow-fleshed sweetpotatoes, which aren’t rich in Vitamin A, and they don’t readily shift to the more nutritious orange-fleshed types. 

By promoting products made from OFSP that can be consumed year-round, also in the cities, CIP can strengthen the campaign against VAD while providing more stable incomes for farmers, and the vine growers who provide them with planting material.  Many options have been tried, and the sweetpotato puree appears to be economical and versatile as an ingredient for many food products.  Indeed, it can replace between 20 and 45% of the wheat flour in baked products such as bread and biscuits.

OFSP roots are pureed and vacuum packed at the Organi Ltd factory. Photo C. Bukania/CIP-SSA

The Organi Ltd factory has a capacity to process 200 kilograms of roots per hour, and produce 1 ton of puree a day. The company buys about 20 tons of OFSP roots per month from local smallholder farmers, most of who are women, whereas a number of youths are employed at the factory for grading, washing, cleaning, peeling, cooking, and mashing OFSP roots into puree. The puree is vacuum packed in 3- to 5-kg bags and shipped to Tuskys, the largest supermarket chain in Kenya.  

Tuskys’ central bakery produces more than 3,000 loaves of OFSP bread per day, as well as buns and muffins, for sale at its 23 stores in the greater Nairobi area.  Consumer studies conducted in Tuskys supermarkets found that sweetpotato bread is well liked, and since the puree costs less than wheat flour, it is actually sold at a lower price. The bread is also a good source of beta-carotene, which our bodies convert into vitamin A. Lab analysis conducted by CIP and the Biosciences eastern and central Africa-International Livestock Research Institute (BecA-ILRI) Hub determined that two slices of the OFSP bread provide the equivalent of 10 percent of the daily vitamin A requirement for children.

“Orange fleshed sweetpotato puree is a versatile ingredient in culinary and food processing applications and will revolutionize the way to eat root and tuber crops in Africa,” says Muzhingi, a specialist in food science and nutrition-sensitive agriculture.

 

OFSP bread has become so popular that the Organi Ltd factory now bakes and sells loaves. Photo M. Friedmann/RTB

OFSP bread has become so popular that Organi Ltd set up some ovens in the puree factory and now bakes its own bread to sell locally. It smelled good, looked very nice, and when I gave a loaf a gentle squeeze, it felt just right!

According to Muzhingi, Organi Ltd purchases OFSP from smallholder farmers for almost double the price on the local markets, and since most of those suppliers are women, the income helps cover the day-to-day household needs of some very needy families. “The OFSP puree value chain is a win-win for everyone and we are looking forward to scaling out and scaling up in the region,” he says.

The puree factory needs a steady supply of OFSP roots, so CIP works to ensure that local farmers can produce enough. This requires an ample supply of virus-free OFSP vines for planting material, because sweetpotato viruses can significantly lower yield, especially when infected vines are replanted. Consequently, the project trains some farmers to become decentralized vine multipliers, and the Kenya Plant Health Inspectorate Services provides them with virus-free starter material derived from tissue culture plantlets that have been screened for viruses. Vine producers are essential for Organi Ltd to be able to scale up production, or for other puree producers to come on board, as demand for OFSP baked goods grows. 

I was thus happy to visit a vine multiplier named Teresa at her farm in Homa Bay County, near Kisumu, in Western Kenya, which is a major sweetpotato production area. She showed us the two small net tunnels that she grows planting material in, in order to protect the vines from the whiteflies that spread sweetpotato viruses.  Teresa and her husband became vine multipliers and learned to use the net tunnels thanks to CIP’s Scaling up Sweetpotato through Agriculture and Nutrition (SUSTAIN) project, and they produce planting material of the Kabode and Vitaa OFSP varieties, which were bred at NARO-Uganda in collaboration with CIP.

Teresa was a gracious host, and she explained the various challenges that she and other OFSP vine multipliers face. She mentioned that many farmers still prefer the white and yellow local varieties, which are freely exchanged among farmers, unlike the OFSP vines that farmers have to purchase from vine multipliers. As part of efforts to promote the consumption of OFSP, CIP and partners work with rural health clinics to educate pregnant women and mothers about the value of eating OFSP and feeding it to their children, while linking them to vine multipliers such as Teresa, who can supply them with virus-free planting materials.

Teresa and other vine multipliers grow OFSP planting material in net tunnels. Photo M. Friedmann/RTB

“I have to encourage the farmers I meet at the health facilities to plant OFSP,” Teresa explains. “Other farmers come to my farm and ask me why I plant OFSP and where they can find a market for it. I am happy to introduce them to people at Organi Ltd.” 

As demand for OFSP baked goods grows, more farmers should start growing those varieties, which will increase demand for virus-free planting material. And the more farmers that grow OFSP in a community, the greater that likelihood that the children and women of child-bearing ages who benefit most from that nutritious crop will eat it regularly.  

By educating people about the benefits of eating OFSP while building demand for the crop in both urban and rural areas, CIP aims to reduce the incidence of VAD and improve farmer incomes.

  • hellen

    This is awesome..i currently produce sweet potato flour from the orange fleshed sweet potato, i hope to start baking bread soon.. i love to support farmers in the value chain as we work to improve nutrition for rural communities. Hellen in kericho

    • Michael Friedmann

      Hellen, thanks for your comment-hope your baking enterprise goes well. You may wish to consider also the puree option for baking, as it also has advantages.