Volatile Compounds

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 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.[1]

Physicochemical Properties

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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.[2]

Chemical Composition

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Compared to starches like D. ibunra 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.[3] 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. [4] 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. [5]

https://en.wikipedia.org/wiki/Digitaria_exilis


Notes

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  1. ^ Lasekan, OO, Teixeira, JPF,Salva, TJG (2001). Volatile flavor compounds of cooked acha (Digitaria exilis stapf). Food Chemistry 75: 333-337.
  2. ^ Arueya, GL, Oyewaye, TM (2015). Effect of varying degrees of succinylation on the functional and morphological properties of starch from acha (Digitaria exilis kippis stapf). Food Chemistry 177: 258-266.
  3. ^ Jideani, IA, Takeda, Y, Hizukuri, S (1996). Structures and physicochemical properties of starches from acha (Digitaria exilis), ibunra (D-ibunra), and tamba (Eleusine coracana). Cereal Chemistry 73: 677-685.
  4. ^ Irving, DW, Jideani, IA (1997). Microstructure and composition of Digitaria exilis stapf (acha): a potential crop. Cereal Chemistry 74: 224-228.
  5. ^ 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.