No abstract

In Africa a variety of indigenous cereals, legumes and tubers are cultivated as starchy food crops. These include sorghum, millet species including pearl millet, finger millet, teff and white and black fonio, and African rice as cereals; cowpea, Bambara groundnut, African yambean and West African locust bean as legumes; and Zulu round potato and the Livingstone potato as tubers. Many of these plants are considered as 'lost crops of Africa'. This paper critically reviews the literature on the physical, chemical, and functionality of their starches. Information is essentially limited to the native starches of sorghum, some millets and cowpea. Livingstone potato starch information is essentially absent. Notable characteristics of African starches include that teff and finger millet have compound starch granules.. Some of the starches have unique properties which could be valuable. The very small granular size of teff and its functional properties can be exploited as a fat replacer. The high retrogradation of cowpea starch has potential in gluten-free pasta and noodles. Nonfood applications for the African starches should be considered in the growing mining and oil industries in Africa.

Fonio is a West African millet with potential for gluten-free products. Sourdough fermentation improves fonio bread quality. To determine the cause, the effects of sourdough fermentation on the dough quality and starch characteristics of two white and two black fonio types and a white sorghum type were investigated. Sourdough fermentation substantially improved the dough consistency making it more similar to bread wheat flour, as measured by the Mixolab. Sourdough fermentation also increased pasting viscosity, an indication of effects on starch. SEM indicated that sourdough fermentation caused some slight swelling and starch leaching from the fonio starch granules. This was confirmed by an increase in damaged starch. It also caused a substantial reduction in starch gel firmness. Principal component analysis clearly separated fermented and unfermented fonio flours. Damaged starch was associated with fermented fonio, as were Mixolab parameters related to dough stability. Sourdough fermentation thus improves fonio dough and bread quality by bringing about slight changes in the starch granules, which probably increase water absorption and hence improve dough strength and gas holding.

Running head: Waxy and high protein digestibility sorghum 1 HIGHLIGHTS Combined waxy-high protein digestibility traits in sorghum gave high peak viscosity High protein digestibility overrode the waxy trait giving floury endosperm texture Combined waxy-high protein digestibility traits gave high flour water solubility Flour solubility of waxy-high protein digestibility traits was similar to wheat flour 2 AbstractNovel biofortified sorghum lines have been developed with both waxy starch (high amylopectin) and high protein digestibility traits. Eight sorghum lines with different combinations of waxy, non-waxy, high-and normal-protein digestibility traits were studied in relation to flour properties. Lines with the high protein digestibility trait had loosely packed starch granules and floury endosperm, irrespective of whether they were waxy or non-waxy.In terms of thermal properties, waxy-high digestibility lines had the highest onset endothermic temperature as well as endothermic energy compared to non-waxy-normal protein digestibility lines. The waxy-high protein digestibility lines had higher paste viscosity and formed much softer and less sticky pastes than the non-waxy, normal protein digestibility lines. Flours of the waxy-high protein digestibility sorghum lines had much higher solubility than the non-waxy-normal protein digestibility lines. At 30 o C flour solubility, waxy-high protein digestibility sorghum lines flour was similar to commercial wheat bread flours. The high flour solubility, high pasting viscosity and soft paste of sorghum lines with combined waxy and high protein digestibility traits indicates that their flours are likely to produce more functional doughs and hence better quality food products than normal non-waxy, normal protein digestibility sorghums.3

No abstract