''Digitaria exilis'', referred to as findi or fundi in areas of Africa, such as The Gambia, with English

common name In biology, a common name of a taxon or organism (also known as a vernacular name, English name, colloquial name, country name, popular name, or farmer's name) is a name that is based on the normal language of everyday life; and is often contrast ...

s white

fonio Fonio is the term for two cultivated grasses in the genus '' Digitaria'' that are notable crops in parts of West Africa. They are millets with small grains. Fonio is a nutritious food with a favorable taste. It is consumed mainly in West Afric ...

, fonio millet, and hungry rice or acha rice, is a grass species. It is the most important of a diverse group of wild and domesticated '' Digitaria'' species known as

that are harvested in the savannas of

West Africa West Africa or Western Africa is the westernmost region of Africa. The United Nations defines Western Africa as the 16 countries of Benin, Burkina Faso, Cape Verde, The Gambia, Ghana, Guinea, Guinea-Bissau, Ivory Coast, Liberia, Mali ...

. The grains are very small. It has potential to improve nutrition, boost food security, foster rural development and support sustainable use of the land. Despite its valuable characteristics and widespread cultivation, fonio has generally received limited research and development attention, which is also why the species is sometimes referred to as an

underutilized crop Neglected and underutilized crops are terms used to describe domesticated plant species used in previous centuries for food, fibre, fodder, oil or medicinal properties, but which have in recent times, been reduced in importance and value for vario ...

. The name (borrowed by English from French) is from Wolof ''foño''. Fonio has continued to be important locally because it is both nutritious and one of the world's fastest growing cereals, reaching maturity in as little as six to eight weeks. It is a crop that can be relied on in semi-arid areas with poor soils, where rains are brief and unreliable. The grains are used in porridge and couscous, for bread, and for beer. The small grains make it difficult and time-consuming to remove the

husk Husk (or hull) in botany is the outer shell or coating of a seed. In the United States, the term husk often refers to the leafy outer covering of an ear of maize (corn) as it grows on the plant. Literally, a husk or hull includes the protective ...

. Traditional methods include pounding it in a mortar with sand (then separating the grains and sand) or "popping" it over a flame and then pounding it (which yields a toasted color grain; this technique is used among the

Akposso The Kposo or Akposso people ( kpo, Akpɔsɔ) are an ethnic group living in the Plateau Region of southern Togo, west of Atakpamé, and across the border in Ghana. Their ethnic language is Kposo or Ikposo. Economy Akposso farmers grow cocoa an ...

). The invention of a simple fonio husking machine offers an easier mechanical way to dehusk. The genetic diversity of ''Digitaria exilis'' varies from region to region in Africa. For example, not much genetic diversity was detected among the domesticated ''Digitaria exilis'' landraces from Mali.Koreissi-Dembélé, Y., Fanou-Fogny, N., Hulshof, P., & Brouwer, I. (2013). Fonio (Digitaria exilis) landraces in Mali: Nutrient and phytate content, genetic diversity and effect of processing. Journal of Food Composition and Analysis, 29(2), 134-143. In contrast, large levels of genetic diversity were detected among the domesticated ''Digitaria exilis'' landraces of the Upper Niger River Basin of West Africa.Adoukonou-Sagbadja, H., Wagner, C., Dansi, A., Ahlemeyer, J., Daïnou, O., Akpagana, K., & Friedt, W. (2007). Genetic diversity and population differentiation of traditional fonio millet (''Digitaria'' spp.) landraces from different agro-ecological zones of West Africa. ''Theoretical and Applied Genetics'', 115(7), 917-931. The many different landraces of ''Digitaria exilis'' are affected differently by the various processing methods. The

European Commission The European Commission (EC) is the executive of the European Union (EU). It operates as a cabinet government, with 27 members of the Commission (informally known as "Commissioners") headed by a President. It includes an administrative body ...

with the EU Regulation L 323/1 of December 19, 2018 approved the commercialization in Europe of Fonio as Novel Food, upon the scientific dossier managed and submitted by “the applicant” Italian company Obà Food.

Description

The fonio is an annual, erect

herbaceous plant Herbaceous plants are vascular plants that have no persistent woody stems above ground. This broad category of plants includes many perennials, and nearly all annuals and biennials. Definitions of "herb" and "herbaceous" The fourth edition ...

which reaches stature heights from 30 to 80 centimeters. The ears consist of two to five narrow part ears, which are up to 15 centimeters long. The spikelets comprise a sterile flower and a fertile flower, the latter of which gives rise to the fonio grain. The grain is a

caryopsis In botany, a caryopsis (plural caryopses) is a type of simple fruit—one that is monocarpellate (formed from a single carpel) and indehiscent (not opening at maturity) and resembles an achene, except that in a caryopsis the pericarp is fuse ...

, which remains surrounded by glumes and

s. Its size is very small, only 1.5 mm (around 2000 seeds to 1 gram). The colour ranges from white, yellow and purple. Fonio matures faster than all other cereals. Some varieties can already be harvested 42–56 days after sowing. Others ripen more slowly, usually in 165–180 days.

Varieties

Identified varieties of ''Digitaria exilis'' are: *var. ''gracilis'' -

Kankan Kankan ( Mandingo: Kánkàn; N’ko: ߞߊ߲ߞߊ߲߫) is the largest city in Guinea in land area, and the third largest in population, with a population of 1 980 130 people as of 2020. The city is located in eastern Guinea about east of the ...

region (Guinea) *var. ''stricta'' -

Casamance , settlement_type = Geographical region , image_skyline = Senegal Casamance.png , image_caption = Casamance in Senegal , image_flag = Flag of Casamance.svg , image_shield = , motto ...

(Senegal), Guinea, Mali, and Burkina Faso *var. ''rustica'' -

Casamance , settlement_type = Geographical region , image_skyline = Senegal Casamance.png , image_caption = Casamance in Senegal , image_flag = Flag of Casamance.svg , image_shield = , motto ...

(Senegal), Guinea, Mali, and Burkina Faso *var. ''mixta'' -

Guinea Guinea ( ),, fuf, 𞤘𞤭𞤲𞤫, italic=no, Gine, wo, Gine, nqo, ߖߌ߬ߣߍ߫, bm, Gine officially the Republic of Guinea (french: République de Guinée), is a coastal country in West Africa. It borders the Atlantic Ocean to the we ...

*var. ''densa'' -

Togo Togo (), officially the Togolese Republic (french: République togolaise), is a country in West Africa. It is bordered by Ghana to the west, Benin to the east and Burkina Faso to the north. It extends south to the Gulf of Guinea, where its c ...

Origin and regions of cultivation

Fonio is one of the ancient African crops, possibly the oldest West African crop as its cultivation seems to have started about 7,000 years ago. The first references to Fonio as food are reported from the mid-14th century. ''D. exilis'' was originally derived from the wild species '' D. longiflora''. Significant cultivation is in West Africa from

Chad Chad (; ar, تشاد , ; french: Tchad, ), officially the Republic of Chad, '; ) is a landlocked country at the crossroads of North and Central Africa. It is bordered by Libya to the north, Sudan to the east, the Central African Republic ...

Cape Verde , national_anthem = () , official_languages = Portuguese , national_languages = Cape Verdean Creole , capital = Praia , coordinates = , largest_city = capital , demonym ...

, south

Mali Mali (; ), officially the Republic of Mali,, , ff, 𞤈𞤫𞤲𞥆𞤣𞤢𞥄𞤲𞤣𞤭 𞤃𞤢𞥄𞤤𞤭, Renndaandi Maali, italics=no, ar, جمهورية مالي, Jumhūriyyāt Mālī is a landlocked country in West Africa. Ma ...

, in western

Burkina Faso Burkina Faso (, ; , ff, 𞤄𞤵𞤪𞤳𞤭𞤲𞤢 𞤊𞤢𞤧𞤮, italic=no) is a landlocked country in West Africa with an area of , bordered by Mali to the northwest, Niger to the northeast, Benin to the southeast, Togo and Ghana t ...

, eastern

Senegal Senegal,; Wolof: ''Senegaal''; Pulaar: 𞤅𞤫𞤲𞤫𞤺𞤢𞥄𞤤𞤭 (Senegaali); Arabic: السنغال ''As-Sinighal'') officially the Republic of Senegal,; Wolof: ''Réewum Senegaal''; Pulaar : 𞤈𞤫𞤲𞤣𞤢𞥄𞤲𞤣𞤭 ...

, northern

, north

Benin Benin ( , ; french: Bénin , ff, Benen), officially the Republic of Benin (french: République du Bénin), and formerly Dahomey, is a country in West Africa. It is bordered by Togo to the west, Nigeria to the east, Burkina Faso to the nort ...

, parts of north central Nigeria such as northern

Plateau State Plateau State is the twelfth-largest Nigerian state. It is in the centre of the country includes a range of hills surrounding the Jos Plateau, its capital, and the entire plateau itself. Plateau State is described as "The Home of Peace and Tou ...

Southern Kaduna Southern Kaduna (formerly Southern Zaria) is an area inhabited by various non-Hausa peoples living south of Zaria Emirate of Kaduna State. It is located in the Middle Belt region of Nigeria. Southern Kaduna consist of 12 local Government out of ...

, parts of

Niger State Niger is a state in the North Central region of Nigeria and the largest state in the country. Niger state has three political zones, zone A,B and C. The state's capital is at Minna. Other major cities are Bida, Kontagora and Suleja. It was ...

Abuja Abuja () is the capital and eighth most populous city of Nigeria. Situated at the centre of the country within the Federal Capital Territory (FCT), it is a planned city built mainly in the 1980s based on a master plan by International Plan ...

(FCT),

Zuru Zuru is a Local Government Area in Kebbi State, Nigeria. Its headquarters is in the town of Zuru. It is also the Headquarters of Zuru Emirate. The Emirate comprises four local government areas, namely: Wasagu/Danko, Fakai, Sakaba and Zuru. I ...

area of

Kebbi State Kebbi state ( ha, Jihar Kebbi; Fulfulde: Leydi Kebbi 𞤤𞤫𞤴𞤣𞤭 𞤳𞤫𞤦𞥆𞤭) is a state in the northwestern Nigeria, Kebbi state is bordered east and north of Sokoto and Zamfara states, and to the south by Niger state while ...

, some parts of

Nasarawa State Nasarawa State is a state in the North Central region of Nigeria, bordered to the east by the states of Taraba and Plateau, to the north by Kaduna State, to the south by the states of Kogi and Benue, and to the west by the Federal Capital Ter ...

and

Kogi State Kogi State is a state in the North Central region of Nigeria, bordered to the west by the states of Ekiti and Kwara, to the north by the Federal Capital Territory, to the northeast by Nasarawa State, to the northwest by Niger State, to t ...

, as well as parts of

Bauchi State Bauchi State (Fula: ''Leydi Bauchi'' 𞤤𞤫𞤴𞤣𞤭 𞤦𞤢𞤵𞤷𞥅𞤭) is a state in the North-East geopolitical zone of Nigeria, bordered by Kano and Jigawa to the north, Taraba and Plateau to the south, Gombe and Yobe to the e ...

. It is also found in south

Niger ) , official_languages = , languages_type = National languagesJos-Bauchi Plateau in Nigeria and the northern regions of Togo and Benin. Fonio is grown in parts of the

Dominican Republic The Dominican Republic ( ; es, República Dominicana, ) is a country located on the island of Hispaniola in the Greater Antilles archipelago of the Caribbean region. It occupies the eastern five-eighths of the island, which it shares with ...

, first only grown as a weed, but it is now cultivated again. Source:

Yield

More than 550 000 ha of fonio are grown each year in West Africa and the production runs at 587 000 tons. Yields are relatively stable, the yield average is currently 1 ton per hectare (ha). In the peripheral regions the yields are less than 500 kilograms and drop when in very poor soils down to 150 to 200 kilograms.

Climate and soil requirements

Fonio is cultivated in West Africa under tropical climate, with a pronounced dry season, temperatures between 25-30 °C and annual rainfalls of 600 to 1200 mm. Nevertheless, Fonio is also grown in higher altitude: over 1000 m, with higher annual rainfalls (1200 to 1500 mm) and colder temperatures (15-25°). Fonio has a well developed root system, which can reach more than one meter depth in the soil. This root system explains the good performance of the plant during the dry season and its adaptation to poor and low fertility soils. Fonio is mainly grown on sandy soils, but can also grow on rocky soils. It also thrives on acidic clay soils with a high aluminium content. On heavy soils, most varieties thrive badly. This crop is low demanding and can cope with unfavourable climate and soil conditions.

Field management

Throughout Africa, most of the work is done by hand.

Before sowing

The main tasks to do before sowing are the cleaning of the field and ploughing. Sometimes animals are used for ploughing or a '' daba'' is utilized to do a superficial scratching.

Sowing and upkeep

The sowing time starts with the first rainfalls. This can vary depending on the variety and the geographical area of cultivation. The grains used for sowing are the best grains kept from the precedent harvest and are sown by hand (broadcast seeding). Sometimes the seeds are mixed with sand to have a more homogenous repartition on the soil. The seeds remain on the surface, so successive harrowing by hand or with the daba is needed to bury them slightly in the soil. Normally 30–40 kg/ha of seeds are used, but sometimes more than 70 kg/ha are sown, in order to control weeds at time of emergence. For germination and emergence a temperature of 30 °C is optimal. The germination and growth is rapid, and for the upkeep of the crop only weeding is needed.

Pests

Insect pests include: *shoot flies, '' Atherigona'' spp. *stem borer, ''

Chilo partellus ''Chilo partellus'', the spotted stalk borer or spotted stem borer, is a moth in the family Crambidae. It was described by Charles Swinhoe in 1885. It is found in India, Pakistan, Iran, Ethiopia, Lesotho, Madagascar, Malawi, South Africa, Sudan, ...

'' *some species of

thrip Thrips (order Thysanoptera) are minute (mostly long or less), slender insects with fringed wings and unique asymmetrical mouthparts. Different thrips species feed mostly on plants by puncturing and sucking up the contents, although a few are ...

s, bugs, and

grasshopper Grasshoppers are a group of insects belonging to the suborder Caelifera. They are among what is possibly the most ancient living group of chewing herbivorous insects, dating back to the early Triassic around 250 million years ago. Grasshopp ...

s *white-backed plant hopper, '' Sogatella furcifera'' (vector of the pangola stunt virus)

Harvest and post-harvest processing

Most of the

harvest Harvesting is the process of gathering a ripe crop from the fields. Reaping is the cutting of grain or pulse for harvest, typically using a scythe, sickle, or reaper. On smaller farms with minimal mechanization, harvesting is the most l ...

ing is still done by hand. As soon as the grains reach maturity, usually in July or August, men cut the fonio with

sickle A sickle, bagging hook, reaping-hook or grasshook is a single-handed agricultural tool designed with variously curved blades and typically used for harvesting, or reaping, grain crops or cutting Succulent plant, succulent forage chiefly for feed ...

s while women and children gather it into sheaves. A motor-driven

mower A mower is a person or machine that cuts (mows) grass or other plants that grow on the ground. Usually mowing is distinguished from reaping, which uses similar implements, but is the traditional term for harvesting grain crops, e.g. with reape ...

may be used to assist in this. The sheaves must be stored in a dry and well ventilated area to prevent mould formation. During the dry season, sheaves are piled to large stacks in the sun to completely dry them.

Threshing Threshing, or thrashing, is the process of loosening the edible part of grain (or other crop) from the straw to which it is attached. It is the step in grain preparation after reaping. Threshing does not remove the bran from the grain. History ...

is done manually as well. Tractor-driven threshers are rarely used due to higher costs and a higher loss of the small grains. Grains are stored loosely. Hulls must be removed before consumption as they are not digestible. This process is traditionally carried out by women using

mortars Mortar may refer to: * Mortar (weapon), an indirect-fire infantry weapon * Mortar (masonry), a material used to fill the gaps between blocks and bind them together * Mortar and pestle, a tool pair used to crush or grind * Mortar, Bihar, a villag ...

. After the fifth hulling, the fonio is called "whitened". Adhering grit and sand is washed away with the help of

gourds Gourds include the fruits of some flowering plant species in the family Cucurbitaceae, particularly ''Cucurbita'' and '' Lagenaria''. The term refers to a number of species and subspecies, many with hard shells, and some without. One of the earl ...

. This process requires a highly skilled woman and up to 10 liters of clean water per one kilogram of fonio. Industrial machinery has been developed to replace the traditional, labour-intensive process described above. It is possible to adapt rice

threshing machines A threshing machine or a thresher is a piece of farm equipment that threshes grain, that is, it removes the seeds from the stalks and husks. It does so by beating the plant to make the seeds fall out. Before such machines were developed, threshi ...

for use on fonio.

Winnowing Winnowing is a process by which chaff is separated from grain. It can also be used to remove pests from stored grain. Winnowing usually follows threshing in grain preparation. In its simplest form, it involves throwing the mixture into the ...

machines or rotational sieves may then be used to clean threshed seeds. CIRAD developed the GMBF hulling machine specifically for use on fonio. However, due to the high cost and performance of such machines, multiple villages must operate the machines together for the investment to be economically viable. ''Digitaria exilis'' is a crop that has not been pursued for domestication worldwide, but has many qualities that make it a good crop candidate. ''Digitaria exilis'' is an annual plant with a C4 metabolism and medium height. It can be planted on its own or in the marginal land, among other crops. Farmers value how quickly ''Digitaria exilis'' matures. The crop reaches maturity in as little as six to eight weeks. ''Digitaria exilis'' is an important part of cooking in West Africa, traditionally used for porridges and steamed cooked foods. The species is known to have high levels of carbohydrate and protein.Jideani IA (2000) Traditional and possible technological uses of ''Digitaria exilis'' (acha) and ''Digitaria iburua'' (iburu). ''Plant Foods for Human Nutrition'' 54: 363-374. These protein levels are seen with ''Digitaria exilis'' being rich in essential amino acids such as methionine compared to other cereals such as wheat, rice and maize. These qualities show that ''Digitaria exilis'' could be a good food source, and that if the right characters are chosen, it could turn into a useful crop. ''Digitaria exilis'' also has good sustainability qualities and can survive in difficult environments. After being exposed to washing and scarifying treatments, the crop maintained germination rates. ''Digitaria exilis'' has also germinated well in various soil types, such as sand and loam. The crop requires little input and can survive on rain. It is adapted to marginal land: it does well in poor soil and is drought resistant.Adoukonou-Sagbadja H, Wagner C, Dansi A, Ahlemeyer J, Daienou O, Akpagana K, Ordon F, Friedt W (2007) Genetic diversity and population differentiation of traditional fonio millet (Digitaria spp.) landraces from different agro-ecological zones of West Africa. ''Theoretical and Applied Genetics'' 115(7): 917-931. All these characteristics make ''Digitaria exilis'' a potential good crop candidate. ''Digitaria exilis'' can be harvested in a number of ways. Some farmers uproot them to get the seeds, but other methods may be more effective. Sickles are used to cut the part of the plant containing the seeds rather than destroying the whole plant. Threshing varies from region to region. Methods include beating the straw to extract the grain, or trampling the straw to extract the seeds. Afterwards the grains have to be dried, usually over the period of a few days. The crop has very small seeds surrounded by hard kernels, so its grains are ground into a fine powder before being used in cooking.Adoukonou-Sagbadja H, Dansi A, Vodouhè R, Akpagana K (2006) Indigenous knowledge and traditional conservation of fonio millet (Digitaria exilis, Digitaria iburua) in Togo. ''Biodiversity and Conservation'' 15: 2379-2395 On the other hand, ''Digitaria exilis'' has some implications for its ability to be a crop candidate. One thing the crop struggles with is in competing with weeds. Farmers are therefore required to remove weeds after sowing. Another issue is that after planting ''Digitaria exilis'', the fields require time to recover soil nutrients. Usually the field has to left fallow for 1–2 years after harvest. These are some of the qualities that need improvement and whose improvement can be achieved through artificial selection. ''Digitaria exilis'' is the oldest native cereal crop in West Africa, first harvested around 5 millennia BC. ''Digitaria exilis'' is vital for food security in the region. Farmers emphasize the crop's culinary value, its short growth cycle, high productivity and medium size. However, due to a lack of harvesting and processing technology, it is difficult to maintain the crop's genetic diversity or establish large-scale production. With that in mind, it is important to maintain and develop fonio for both producers and consumers. ''Digitaria exilis'' has many potential future uses in cooking or as technological feedstock so it is necessary to select for good kernel properties to develop it into a new crop for the world.

Nutritional value of ''Digitaria exilis''

''Digitaria exilis'' holds high nutritional value to humans. The nutritional value of hulled fonio is about 1470 kJ and for whitened fonio 1430 kJ per 100 gram. The nutritional value of its product is very high without suffering from taste. Furthermore, it is a good source of fibres and phytonutrients. It contains

methionine Methionine (symbol Met or M) () is an essential amino acid in humans. As the precursor of other amino acids such as cysteine and taurine, versatile compounds such as SAM-e, and the important antioxidant glutathione, methionine plays a critical ...

and

cysteine Cysteine (symbol Cys or C; ) is a semiessential proteinogenic amino acid with the formula . The thiol side chain in cysteine often participates in enzymatic reactions as a nucleophile. When present as a deprotonated catalytic residue, some ...

, two amino acids that are important to human survival. These two amino acids, however, are lacking in wheat, rice, maize, and other cereal crops. Moving from the amino acid level to the macromolecule level, ''D. exilis,'' compared to other cereal crops, has greater protein, carbohydrate, and fiber content.Barikmo I., Quattara F., & Oshaug A. (2004). Protein, carbohydrate and fibre in cereals from Mali - how to fit the results in a food composition table and database. Journal of Food Composition and Analysis, 17 (3-4), 291-300. ''Digitaria exilis'' has more protein and fiber content than rice. Additionally, ''D. exilis'' has more carbohydrate content than millet, sorghum, and maize. Therefore, the nutritional benefit from ''D. exilis'' outweighs the nutritional benefits from other similar cereal crops. Content of Carbohydrates, Lipids, Proteins and Minerals of ''Digitaria exilis'' compared to other cereals (% dry weight) Source:

Mineral content

''D. exilis'' shows generally mineral contents that are in the range of other cereals (Table 1). However, it contains much more sulphur than other cereals. Furthermore, the sulphur concentrates primarily in the grain rather than the husk as with other cereals. This leads to ''D. exilis'' containing twice as much

- a sulphur compound - as corn or millet, and three times as much as rice does. Some of the minerals are concentrated in the husk, which is lost during the hulling process. The remaining fatty acids in the hulled grain are mainly unsaturated fats like linoleic and oleic acid. The most present saturated fat is palmitic acid. It has been reported that ''Digitaria exilis'' is an optimal food for people having diabetic problems. . Mineral content of Digitaria exilis, hulled and whitened Source:

Effect of processing on nutritional values of ''Digitaria exilis''

There are several factors that can alter this pre-existing high nutritional content. One method that distorts the nutritional composition of ''D. exilis'' is the extensive processing required to bring it to an edible state. During milling, the outer layers of its grains are removed, and these layers are where the nutrients are primarily located. Therefore, with the loss of the outer layers of the grains, there is a loss in the nutrient content. As a result, the iron, zinc, and phytate concentrations present in the edible form of ''D. exilis'' are reduced in abundance relative to their respective concentrations before processing.

''Digitaria exilis'' and gluten

Coeliac disease Coeliac disease (British English) or celiac disease (American English) is a long-term autoimmune disorder, primarily affecting the small intestine, where individuals develop intolerance to gluten, present in foods such as wheat, rye and barle ...

is an intolerance to wheat

gluten Gluten is a structural protein naturally found in certain cereal grains. Although "gluten" often only refers to wheat proteins, in medical literature it refers to the combination of prolamin and glutelin proteins naturally occurring in all grai ...

, a

prolamine Prolamins are a group of plant storage proteins having a high proline amino acid content. They are found in plants, mainly in the seeds of cereal grains such as wheat (gliadin), barley (hordein), rye (secalin), corn (zein), sorghum (kafirin), and ...

, which can cause chronic small intestinal problems. Fonio is closer to

sorghum ''Sorghum'' () is a genus of about 25 species of flowering plants in the grass family (Poaceae). Some of these species are grown as cereals for human consumption and some in pastures for animals. One species is grown for grain, while many other ...

and rice than to wheat, and therefore it does not contain the sequence of amino acids that cause this intolerance. Fonio is therefore of interest to people suffering from coeliac disease.

Effect of agricultural practice on nutritional values of ''Digitaria exilis''

Additionally, the nutrient content and yield of ''D. exilis'' can be affected by the soil nutrition present in the varying climatic conditions of West Africa, which is where ''D. exilis'' primarily grows.Gigou, J., Stilmant D., Diallo T., Cisse N., Sanogo M., Vaksmann M., & Dupuis B. (2009). Fonio millet (''Digitaria exilis'') response to N, P and K fertilizers under varying climatic conditions in West Africa. Experimental Agriculture, 45 (4), 401-415. Through experimentation, it was seen that the nitrogen concentration in the soil has the greatest effect on the nutrition and productivity of ''D. exilis''. When nitrogen was added to the soil in limited quantities with an excess of potassium and phosphorus, productivity of ''D. exilis'' increased by 22%. Such significant results were not observed, however, when either potassium or phosphorus was added to the soil with excess nitrogen and phosphorus, or with excess nitrogen and potassium, respectively. On the contrary, when nitrogen, phosphorus, and potassium were added to the soil in equal and moderate quantities, the greatest amount of yield and nutrition was seen. This overall trend is seen as a result of the low rainfall and poor soil conditions that ''D. exilis'' naturally grows in. Additionally, farmers evaluated ''D. exilis'' landraces on key agricultural characteristics.Dansi, A., Adoukonou-Sagbadja, H., & Vodouhè, R. (2010). Diversity, conservation and related wild species of Fonio millet (Digitaria spp.) in the northwest of Benin. Genetic Resources and Crop Evolution, 57(6), 827-839. These included ease of processing, productivity, grain size, and facility of harvesting among many others. Based on the evaluations given by these farmers, it can be seen that the agronomic traits (traits that allow for a greater ease of growing to farmers) of ''D. exilis'' would be having a big and long stem, having a long panicle with many grains, and having a large grain size. These traits allow for easier growing and harvesting by farmers. From an evolutionary biology standpoint, information about the nutritional content of ''D. exilis'', factors that modify its nutritional content, and its agronomically important traits can be of importance under artificial selection of ''D. exilis''. The ''Digitaria exilis'' landraces that exhibit the greatest amount of nutrition and display the agriculturally important qualities can be further cultivated under improvement. As a result, ''Digitaria exilis'' can serve as a perennial crop to provide the human species with food security in the future. WWF and Knorr in a joint study, dated February 2019, name ''Digitaria exilis'' as one of the “50 future foods for healthier people and a healthier planet". WWF and the multinational Unilever (Knorr) teamed up to launch a campaign to raise awareness of the 50 Future Foods which people should eat more of in order to help reduce the environmental impact of food productions and to improve human health – ''Digitaria exilis'' has been identified as one of those ingredients.

Volatile compounds

One of the things that makes ''Digitaria exilis'' such a sought after grain is its chemical composition. ''Digitaria exilis'' is an important source of nutrition because it is rich in methionine, which is an amino acid that is vital to human health. Since ''Digitaria exilis'' was such an important part of people's nutrition, researchers wanted to find out what made it taste so good. Volatile compounds were used to determine what contributed to the flavor of ''Digitaria exilis''. It was found that ''Digitaria exilis'' contains several amino acids that readily react with monosaccharides to form alkylpyrazines. There were three types of volatiles: those formed from starch degradation, those formed from reactions between starch and proteins, and those formed through lipid oxidation.

Physicochemical properties

One of the things that makes ''Digitaria exilis'' unique is its physicochemical properties. The physicochemical properties of ''Digitaria exilis'' can differ depending on if its starch is natural or succinylated. The pH of succinylated ''Digitaria exilis'' is lower than that of natural ''Digitaria exilis''. This could be because some of the molecules introduced by succinylation resembled those of acetylation. While succinylation does decrease the pH of starch, it can increase some of its properties such as bulk density and water absorption capacity. The difference in bulk density is caused by the particle size decreasing as the bulk density increases. Succinylation increases the water absorption capacity of the starch which indicates that it could be helpful in some food products such as dough.

Chemical composition

Compared to starches like ''D. iburua'' and ''Eleusine coracana'', ''Digitaria exilis'' has more branched molecules. This was an important finding because although it has more branched molecules, it has fewer chains than the other starches which is unusual chemically. Aside from these differences, most other chemical characteristics were very similar to rice which was not surprising because ''Digitaria exilis'' and rice are both starches of the A. crystalline type. Additionally, the microstructure of ''Digitaria exilis'' was studied, and it was discovered that it is very similar to the grain millets. Researchers found that ''Digitaria exilis'' is most abundant in protein bodies and that most of the protein is located towards the center of the cell. The specific structure of ''Digitaria exilis'' was analyzed and it was found that it is surrounded by thin bracts and two glumes. The caryopsis, a type of fruit that contains a pericarp that is fused with a thin seed coat, of the ''Digitaria exilis'' contains several layers that serve the purpose of protecting the endosperm and embryonic tissues. The composition of fonio can differ depending on what part of the world you are in. The main differences are in the protein and fiber content. This information could be useful in giving people dietary advice if their diet is lacking a certain protein or fiber.Barikmo, I, Outtara, F, Oshaug, A (2004). Protein, carbohydrate and fibre in cereals from Mali-how to fit the results in a food composition table and database. Journal of Food Composition and Analysis 17: 291-300.

Notes

References

External links

Fonio - NUS Community, Bioversity International
{{Taxonbar, from=Q1340738 exilis Millets Grasses of Africa Crops originating from Africa Cereals