Buckwheat (Fagopyrum esculentum), also known as common buckwheat, Japanese buckwheat and silverhull buckwheat, is a plant cultivated for its grain-like seeds and as a cover crop. A related and more bitter species, Fagopyrum tataricum, a domesticated food plant common in Asia, but not as common in Europe or North America, is also referred to as buckwheat. It is not related to wheat, as it is not a grass. Instead, buckwheat is related to sorrel, knotweed, and rhubarb. Because its seeds are rich in complex carbohydrates, it is referred to as a pseudocereal.
Composition of Buckwheat
- 71–78% in groats
- 70–91% in different types of flour
- Starch is 25% amylose and 75% amylopectin.
- Depending on hydrothermal treatment, buckwheat groats contain 7–37% of resistant starch.
- Crude protein is 18%, with biological values above 90%. This can be explained by a high concentration of all essential amino acids, especially lysine, threonine, tryptophan, and the sulphur-containing amino acids.
- Rich in iron (60–100 ppm), zinc (20–30 ppm) and selenium (20–50 ppb)
- 10–200 ppm of rutin, 0.1–2% of tannins and presence of catechin-7-O-glucoside in groats.
It contains 0.4 to 0.6 mg/g of fagopyrins (at least 6 similar substances)
Salicylaldehyde (2-hydroxybenzaldehyde) was identified as a characteristic component of buckwheat aroma. 2,5-dimethyl-4-hydroxy-3(2H)-furanone, (E,E)-2,4-decadienal, phenylacetaldehyde, 2-methoxy-4-vinylphenol, (E)-2-nonenal, decanal and hexanalalso contribute to its aroma. They all have odour activity value more than 50, but the aroma of these substances in an isolated state does not resemble buckwheat.
Nutrition in Buckwheat
In a 100-gram serving providing 343 calories dry and 92 calories cooked, buckwheat is a rich source (20% or more of the Daily Value, DV) of protein, dietary fiber, four B vitamins and several dietary minerals, with content especially high (47 to 65% DV) in niacin, magnesium, manganese and phosphorus. Buckwheat is 72% carbohydrates, including 10% dietary fiber, 3% fat and 13% protein.
As it contains no gluten, it may be eaten by people with gluten-related disorders, such as celiac disease, non-celiac gluten sensitivity or dermatitis herpetiformis. Nevertheless, it may have gluten contamination.
Negative reactions of Buckwheat
Cases of severe allergic reactions to buckwheat and buckwheat-containing products have been reported. It contains fluorescent phototoxic fagopyrins. Seeds, flour, and teas are generally safe when consumed in normal amounts, but fagopyrism can appear in people with diets based on high consumption of its sprouts, and particularly flowers or fagopyrin-rich buckwheat extracts. Symptoms of fagopyrism in humans may include skin inflammation in sunlight-exposed areas, cold sensitivity, and tingling or numbness in the hands.