Search

This work characterized two local and seven improved Cassava Mosaic Disease [CMD]-tolerant cassava varieties for their biochemical composition and viscoelastic (pasting) properties. The biochemical composition and starch pasting properties were evaluated respectively using standard analytical methods and Brabender Viscoamylograph. Cluster dendogram and principal component analyses compared similarities in the nine cassava varieties, thus predicting their varied food and industrial end uses. The different cassava varieties had starch, total sugars and reducing sugars content ranging from 53-69%, 6.5-9.2% and 0.9-2.5%, respectively. The starch content of the cassava varieties on dry weight basis (DW) varied from 54.0% to 69.0% with Nalumino having the lowest and Mweru having the highest respectively. Tanganyika, Mweulu, and Banguerlu also recorded relatively higher starch content of 62.7%, 63.6% and 63.6% respectively. Mweru, Tangayoka, Mweulu, and Bangweulu had fairly high starch content (>60%) and thus could be used for many commercial products such as starches, alcohols and glucose. The viscoelastic properties of the different varieties had pasting temperature (63.5–67.6oC), peak viscosity (402–595 BU), viscosity at 95oC (394–592 BU), viscosity at 50oC (126–254), breakdown viscosity (236–352 BU) and setback (-100–4 BU). Tanganyika recorded the highest pasting temperature (67.6oC), peak viscosity (595 BU), viscosity at 95oC (592 BU) and viscosity at 95oC-hold (317 BU). Bangweulu, Mweulu, Mweru, Manyokola, Nalumino, Kampolombo and Chila A were clustered differently from Chila B and Tanganyika on the basis of their biochemical qualities and pasting properties. These characterizations showed that Tanganyika would be suitable for products requiring high elasticity and gel strength, easier to cook and also more stable during cooking/preparation such as fufu (pounded cassava) and banku or Nshima. Chila A would also be suitable for use as fillers and binders in the baking, confectionery industries as substitutes of wheat flour. The low viscosities of Chila B make it suitable for household food uses such as snacks where the roots are boiled, roasted or toasted and consumed.

Cassava was domesticated in the Amazon Basin, where Native Americans selected many bitter varieties, and devised methods for detoxifying them. Cassava reached Africa in the sixteenth century, where rural people soon learned to remove the cyanogenic toxins, e.g., by drying and fermenting the roots. Processing cassava to remove the cyanogenic toxins including the cyanide formed during the processing is time consuming. The work is often done by women, while women and men often prefer bitter cassava varieties for social reasons and superior taste and color. In spite of deep, local knowledge of safe processing, traditional foods made with contaminated water may contain bacterial and fungal pathogens. Improper storage may encourage mycotoxins, such as aflatoxin. Recent advances in industrial processing are developing foods that are free of toxins and microbial contamination. Processing and selling cassava leaves is an emerging but fast-growing sector. Cassava leaves also contain cyanogenic toxins normally in higher concentrations than the cassava roots. In the future, more attention must be paid to the safe processing of cassava leaves and roots, especially as food processing becomes increasingly industrialized worldwide.