Фонио: Недооцененный злак Западной Африки

Species of grass

Digitaria exilis, referred to as findi or fundi in areas of Africa, such as The Gambia, with English common names white fonio, 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 fonio that are harvested in the savannas of West Africa. 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. 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. 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 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. In contrast, large levels of genetic diversity were detected among the domesticated Digitaria exilis landraces of the Upper Niger River Basin of West Africa. The many different landraces of Digitaria exilis are affected differently by the various processing methods. The European Commission 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.

The fonio is an annual, erect herbaceous plant 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, which remains surrounded by glumes and husks. 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.

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.

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.

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.