



Processing and Marketing

In addition to boiling, steaming, roasting and drying, there are novel ways of preparing sweetpotato, especially the orange-fleshed type (OFSP), to add value to it. For example, fresh grated sweetpotato, boiled and mashed sweetpotato (puree) and sweetpotato flour can replace some of the wheat flour in commonly consumed products.


They can be incorporated into bread, doughnuts, chapati, cakes, biscuits, croissants, pies etc. In addition, sweetpotato flour can be mixed with other flours to produce composite flour that can be used to make porridge for children. Other products from OFSP include sweetpotato jam and ketchup. Sweetpotato leaves can be used to prepare relish. 


The substitution of wheat flour, either with fresh grated OFSP, boiled and mashed OFSP or OFSP flour, is gaining a foothold in the snack product market in East Africa. However, profit depends on the relative cost of sweetpotato roots or flour to wheat flour and the degree of substitution.

Fresh sweetpotato roots outside the main harvest season fetch a much higher market price than sundried sweetpotato root slices or pieces. However, despite significant efforts to find effective ways of storing fresh sweetpotato roots so that they can be used at home or sold to the market over a longer period of time, there is very little use of these methods in sub-Saharan Africa.


Fresh sweetpotato roots are categorized as perishable because once detached from  the plant, unless they are cut into small pieces and sun-dried, they cannot be stored for long periods of time, unlike grain crops. 


Across the world, there are traditional methods of storing fresh sweetpotato roots. Researchers have used these traditional stores as a basis from which to try and develop improved fresh storage. Uptake of fresh root storage is dependent on the expected root price difference between that at harvest time and that a few months later on.  While theoretically, the storage of fresh roots should enable them to sell at higher rates in to the market, there is evidence that many farmers also store them for their own consumption.





Fresh sweetpotato roots are highly perishable due to their high moisture content, sugar content, delicate thin skin, their high respiratory rate after harvest which produces heat and leads to softening of the roots. Shelf life varies by variety. Leaving the harvested storage roots in the sun for a short period is believed to help increase shelf-life, but it can also lead to moisture loss and softening.


The market value of fresh sweetpotato roots can be enhanced through improved post-harvest handling. For example, when the fresh roots are ready to be taken to the market, their value can be enhanced by improving their presentation through washing. Sweetpotato roots can also be sorted by hand to remove any rotting or otherwise unmarketable roots. Though grading and sizing is not commonly done in most parts of Africa, growers, wholesalers and retailers are being encouraged to practice root sorting to improve the value of the product on the market.


Proper packaging is an important step in the journey from the grower to the consumer. Across sub-Saharan Africa, sweetpotato is packed and transported in large sacks that are heavy to carry and are often dropped, causing bruises and other mechanical damage which results to rotting and reduces storage and shelf-lfie of the roots. This may discourage buyers.


Other ways of improving post-handling include labeling of produce to enable growers and others in the value chain to keep track of the source of the roots and the destination, and proper ways of transportation.

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