Millet production in sub Saharan Africa in thousands per tons from 2015 to 2019.
Millets are small to medium size cereal grain crops that are cultivated throughout the tropics and subtropical region. The grains are used for food and fodder for feeding animals around the globe. Millets have great economic, health importance, gluten-free, have low glycemic index and are known as “nutra–cereals”. The grains are mostly utilised as a food source by population with lower socio-economic factors which are traditional consumers in the farm and village levels. They are rich sources of carbohydrates, protein, crude fibre, phytochemicals, minerals, and vitamins. They are processed by using different traditional processes such as soaking, germination, malting, fermentation, milling or grinding, cooking, roasting and popping. Millet grains/ flours are utilised and consumed as flat breads, biscuits, snacks, beverages, porridges, chapati, dosa, pastas. There is a need to produce new value-added products from millets which is underutilised crop to improve food security and prevent micronutrients deficiencies.
- cereal grains
- nutritional composition
- health benefits
Millets are cereal crops that belong to the family
|Countries||Yearly production (in tonnes)|
|Central African Republic||10000||10000||10000||10000||10000|
|Democratic Republic of the Congo||43776||41006||40887||40908||40930|
The millet grains are gluten-free, non-acid forming, easy to digest, low glycemic index and healthy food diet for people with celiac disease – common disease caused by cereal protein ingestion [1, 2, 19, 22]. Other gluten-free cereal grains are maize, brown rice and sorghum while barley, wheat and rye are gluten rich cereal grains . Table 2 and Figure 1 show the major cultivated millet species in the world. Millets are globally grown in different regions from East to West and they are called in different names around the globe which indicate their specific originality such as foxtail millet as Italian millet, proso as French millet and barnyard as Japanese millet . Finger millet originated in East Africa while white fonio (
|Common name||Tribes/genus and species||References|
|Finger millet/||[2, 20]|
|White fonio (||[22, 23]|
|Black fonio (|
|Barnyard millet/||[1, 2, 24]|
|Proso millet/||[13, 20]|
|Kodo millet/||[13, 15]|
|Foxtail millet/||[2, 13]|
|Pearl millet/||[15, 20]|
|Foxtail millet||Pale yellow to red||Ovoid||2 mm long||China|
|Finger millet||Light to dark brown||Spherical||1–2 mm in diameter||East Central Africa (Uganda)|
|Proso millet||White cream, yellow, orange||Spherical oval||3 mm long/ 2 mm diameter||Central and eastern Asia|
|Pearl millet||White, grey, pale yellow, brown, or purple.||Ovoid||3–4 mm in length||Tropical West Africa (Sahel)|
|Kodo millet||Blackish to dark brown||Elliptical and oval||1.2 to 9.5 μm long||Mainly in India also in west Africa|
|Little millet||Grey to straw white||Elliptical and oval||1.8 to 1.9 mm long||Southeast Asia|
|Banyard millet||White||Tiny round||2–3 mm long||Mainly Japan and India|
|Finger millet||It prevents tissue damage and stimulates the wound healing process in diabetic rats. Prevents cardiovascular disease by reducing plasma triglycerides in hyperlipidemic rats.|
|Proso millet||Gluten-free and can prevent humans from celiac disease. Helpful in reducing the risk of type 2 diabetes in humans due to a low glycemic index.|
|Foxtail millet||It prevents colorectal cancer in mice models. Reduces cholesterol level & have an antidiabetic effect on impaired glucose tolerance persons. Capable of attenuating acute ethanol-induced hepatic injury in mice.|
|Pearl millet||Prevention of celiac disease in humans due to gluten-free property. Stimulates the immune system to prevent the Shigella-induced pathogenicity in the mice model.|
|Banyard millet||Acts as an inhibitor of cancer by inducing apoptotic cell death in HT-29 human colon cancer cell line. Its phenolic content inhibits the protein glycation and glycoxidation, which plays a crucial role in the progression of diabetes.|
|Little millet||Prevents from modern metabolic disorders due to the presence of polyphenols.|
|Kodo millet||Reduce glycemic index and prevents diabetes in the human female model, also have antioxidant activities.|
2. Nutritional composition of millet species
Some nutritional values of millets are similar to that of wheat and rice. Millets are staple food for many African countries; however, they are low in macro nutrients such as protein and fat but rich in vitamins and minerals . Millets are a good source of magnesium which reduces the severity of asthma, frequency of migraines, lowers high blood pressure and reduces the risk of heart attacks. These nutrients play important roles in human nutrition . The grains are also a good source of diet for growing children and expectant mothers . They are a good source of phytochemicals such as polyphenols, tannins, and phytic acid which helps to lower cholesterol and reduces cancer risk, high blood pressure, heart disease and diabetes [21, 27]. Other potential health benefits and medical function of millets are increasing in time span of gastric emptying and provides roughage to gastro intestine. Millet is also known as an alkaline forming food. Alkaline based diet is often recommended to get better optimal health and prevent illness/ diseases [7, 29].
Table 5 shows the nutritional composition of some millet’s species. They have higher amount of minerals such as magnesium, manganese, phosphorus, iron, copper, and potassium when compared with corn, sorghum, and wheat [1, 8, 30]. The main nutrients in millets are starch, protein, lipid, dietary fibre, vitamins, and minerals as shown in Table 6. When comparing millet with other cereals, millet contains 75% of carbohydrates and is low in fat (2–5%) content than maize, rice, and sorghum [1, 2, 8]. Other potential health benefits of millets are the development and repair of body tissue, the prevention of gallstones, protection against breast cancer and protection against postmenopausal complications and the reduction of chances of childhood cancer [1, 2]. Millets contain 65–75% of complex carbohydrates, 5.6–12% protein, fat, 2–5%, 15–20% crude fibre and 2.5–3.5% minerals.
|Mineral contents (mg/ kg)||Millet||Wheat||Maize||Rice||Sorghum|
|Contents||Foxtail millet||Kodo millet||Barnyard millet||Pearl millet|
Millets are rich source of antioxidant activity such as phenolic compounds that contains phenolic acids, flavonoids, and tannins. Phenolic acids are sub-divided into hydroxybenzoic acids, hydroxycinnamic acids, hydroxyphenylacetic acids and hydroxyphenylpropanoic acids (Table 7). The phenolic compounds of millets phenols are reported to have antioxidant, anti-mutagenic, anti-oestrogenic, anti-inflammatory, antiviral effects, and platelet aggregation inhibitory activity . The antioxidant activities of foxtail and proso millets are high because of their high total carotenoid and tocopherol content which range from 78 to 366 and 1.3–4.0 mg/100 g. The grain has good nutritional value however it is mostly consumed by traditional consumers in a tribal community. Its products are scarce in the urban areas as compared to rice ready-to-eat products [7, 29]. The major challenge with millet grains is that the commercial industrial method of processing the grains are not well-known or developed as compared to other cereal grains .
|Phenolic compound||Foxtail millet||Kodo millet||Barnyard millet||Pearl millet|
|Hydroxybenzoic acid and derivatives|
|Hydroxycinnamic acid and derivatives|
3. Processing and utilisation of millet grains/flours
Processing is a technology which is used to convert the cereal grains into an edible form of food products. Millet grains are prepared using modern and traditional technologies such as soaking, germination, malting, fermentation, milling or grinding, cooking, roasting, compositing flour, fortification, irradiation and popping or puffing mostly widely used in rural areas [13, 33, 34]. Traditionally, millet grains are spread and dried in the sun for a period of one week and are stored inside the bags for future use or processing. The grains can be stored for 5 to 10 years. These processes improve the consumption, nutritional composition, and sensory attributes of food products. Various studies has been conducted and the researchers have tried to produced millets products like puffed, popped, flaked, extruded and roller dried products; fermented, malted and composite flours; weaning foods. Some of the recent studies are promising to produce popped and milled products . Current and emerging food products produced from millet grains/ flours are shown in Tables 8 and 9.
|Animal feeds||Animal feeds|
|Industrial uses||Industrial uses|
|Traditional opaque beer, Busa|||
|Bread, porridge, soup, cake, beer and distilled liquors|||
|Light and thick porridge; Beer called |||
|Weaning and infant food preparations, dumpling, porridge and roti|||
|Food products: |||
|Polenta, couscous, medicinal herb, folk remedy for leprosy, liver diseases, measles. Pneumonia and smallpox|||
|Flour- based foods such as ||[1, 41]|
Traditional processing of millet products has received poor scientific applications especially in the developing countries and the use of the modern processing technology has been restricted which can help to produce commercialised products in a large industrial volume [13, 42]. The development of value-added and convenient food products in urban areas may be a possible solution for promoting consumption of millets products. Most of the research have been conducted on the development of composite flour and extruded products which also increase the availability of millet products in the urban areas [1, 43]. Presently, food scientists are more interested in neglected small grains such as finger millet to reduce food shortage and hunger in the developing countries such as Nigeria, Uganda, Kenya, Tanzania, and South Africa. People who are living in the developing countries have limited access to animal food products so it is better to consume healthy millet foods that are rich in minerals and vitamin B complex. Animal food products contain high amount of minerals such as iron and zinc [44, 45, 46].
4. Traditional millet-based products
Millet grains/flours are consumed as flat bread, porridge, roasted and alcoholic and non-alcoholic beverages. They are utilised to bake different baked products (cookies, biscuits, bread and muffins) and weaning food. Composite flours are utilised to make chappati, puti and
|Yeast and bacteria||Zimbabwe|
|Botswana and Ghana|
|Botswana and Ghana|
|East African Countries|
|Traditional opaque beer (||South Africa|
|Commercial brewing, opaque beer, ||Zimbabwe|
5. Non-alcoholic beverage products
Some other non-alcoholic beverage products that are produced form different millet species include
In general, this book chapter covered the nutritional composition of millets, processing and utilisation of millets grains or flour into traditional based products and non-alcoholic beverages. Different types of millet such as pearl millet, proso millet, kodo millet, finger millet, foxtail millet and little millet) are currently being utilised for different purposes (bread, cookies, muffins, chapatti and biscuit. The availability of gluten free value-added millet products globally may help mitigate the incidence of celiac disease and obesity. Therefore, there is a need for commercialisation and development of value-added gluten-free food products from millets.
The authors would like to thank, we are changing the funder to Agricultural Research Council: “Human, Research and innovation Capacity Development Initiative (HRICDI)” An Initiative of Department of Science and Technology (DSI), Managed by the “Agricultural Research Council (ARC)”, Title: “Utilisation of traditional processing methods (fermentation and malting) to improve the nutritional value of cereal grains”. Univen grant number, Cost centre E601. Consortium comprises of University of Pretoria & University of Venda, Wageningen University, Finland, Kenya, and Uganda.