Morphology, physical, chemical, and functional properties of starches from cereals, legumes, and tubers cultivated in Africa: A review

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.

Physicochemical properties, modifications and applications of starches from different botanical sources

“…Wild type A-type: Disc-shape (Ellis et al, 1998) B-type: lenticular (Ellis et al, 1998) A-type:10-25 (Ellis et al, 1998) B-type: 5 (Ellis et al, 1998) 0.7-1.2 (Morrison et al, 1984) 0.2-0.4 (Ellis et al, 1998) 19-22.1 (Ellis et al, 1998) 25.3-30.1 (Morrison et al, 1984) Waxy A-type:10-25 (Ellis et al, 1998) B-type: 5 (Ellis et al, 1998) 0.3-0.5 (Morrison et al, 1984) 0.06-0.15 (Ellis et al, 1998) 1.8-3.6 (Ellis et al, 1998) 2.1-8.3 (Morrison et al, 1984) High amylose A-type: 15-32 (Ellis et al, 1998) B-type :2-3 (Ellis et al, 1998) 1.0-1.7 (Morrison et al, 1984) 18.2-24.1 (Ellis et al, 1998) 38.4-44.1 (Morrison et al, 1984) Sorghum Wild type Polygonal, dented and round (Wankhede et al, 1989) 8-14,5 polygonal, 8-10 round (Wankhede et al, 1989) 0.8 (Emmambux & Taylor, 2013) 2.3 (Emmambux & Taylor, 2013) 23.7-27.6 (Boudries et al, 2009) 26-30/A (Boudries et al, 2009) Waxy Larger than normal sorghum (Lawal et al, 2011) 5-25 (Sang et al, 2008) < 0.3 (Sang et al, 2008) 3.5 (Sang et al, 2008) 0 (Sang et al, 2008) Heterowaxy 14 (Sang et al, 2008) …”

“…Non-amylosic components such proteins, lipids and phosphate groups are also important differences in the characteristics of conventional and unconventional starches. Emmambux & Taylor (2013) studied the starch properties of cereals, legumes and tubers grown in Africa. The starch granules of certain cereals and beans possessed the common characteristics of small size, slightly porous surfaces and special paste properties, making them an interesting alternative for industry.…”

Influence of steeping duration, drying temperature, and duration on the chemical composition of sorghum starch

“…Physically achieving this (through steeping) is not only cost effective, safe, relatively easy, but can also significantly improve the quality of sorghum starch and reduce antinutrients (Claver, Zhang, Li, Zhu, & Zhou, ). Sorghum starch has been reported to have similar properties as that of corn and a potentially good source of raw materials for a wide range of uses (Beta, Corke, & Taylor, ; Beta, Obilana, & Corke, ; Emmambux & Taylor, ; Singh, Sodhi, & Singh, ; Srichuwong et al., ).…”

“…has been reported to have similar properties as that of corn and a potentially good source of raw materials for a wide range of uses (Beta, Corke, & Taylor, 2000;Beta, Obilana, & Corke, 2001;Emmambux & Taylor, 2013;Singh, Sodhi, & Singh, 2010;Srichuwong et al, 2017).…”

Developments in modulating glycaemic response in starchy cereal foods

“…However, over time the rate of digestion of larger granules became more rapid. In certain cereal species, notably rice, teff and finger millet, some starch granules are compound, comprising a large structure of tightly packed small granules . With native (raw) compound granules, amylolysis is may be restricted due reduced capacity of the amylases to bind to the granule surface .…”