Buckwheat

Buckwheat (Fagopyrum esculentum), or common buckwheat,[2] is a plant cultivated for its grain-like seeds and as a cover crop. The name "buckwheat" is used for several other species, such as Fagopyrum tataricum, a domesticated food plant raised in Asia. Despite the name, buckwheat is not related to wheat, as it is not a grass. Instead, buckwheat is related to sorrel, knotweed, and rhubarb. Buckwheat is referred to as a pseudocereal because its seeds' culinary use is the same as cereals', owing to their composition of complex carbohydrates.

Buckwheat
Scientific classification
Kingdom:	Plantae
Clade:	Tracheophytes
Clade:	Angiosperms
Clade:	Eudicots
Order:	Caryophyllales
Family:	Polygonaceae
Genus:	Fagopyrum
Species:	F. esculentum
Binomial name
Fagopyrum esculentum Moench
Synonyms[1]
Polygonum fagopyrum L. 1753 Fagopyrum cereale Raf. Fagopyrum dryandrii Fenzl Fagopyrum emarginatum (Roth) Meisn. 1840 Fagopyrum emarginatum Moench 1802 Fagopyrum fagopyrum (L.) H.Karst., invalid tautonym Fagopyrum polygonum Macloskie Fagopyrum sagittatum Gilib. Fagopyrum sarracenicum Dumort. Fagopyrum vulgare Hill ex Druce 1913 Fagopyrum vulgare T.Nees 1853 Polygonum emarginatum Roth

Etymology

The name "buckwheat" or "beech wheat" comes from its triangular seeds, which resemble the much larger seeds of the beech nut from the beech tree, and the fact that it is used like wheat. The word may be a translation of Middle Dutch boecweite: boec (Modern Dutch beuk), "beech" (see PIE *bhago-) and weite (Mod. Dut. tarwe, antiquated Dut. weit), wheat, or may be a native formation on the same model as the Dutch word.[3]

History

Buckwheat, illustration from the Japanese agricultural encyclopedia Seikei Zusetsu (1804)

The wild ancestor of common buckwheat is F. esculentum ssp. ancestrale. F. homotropicum is interfertile with F. esculentum and the wild forms have a common distribution, in Yunnan, a southwestern province of China. The wild ancestor of tartary buckwheat is F. tataricum ssp. potanini.[4]

Common buckwheat was domesticated and first cultivated in inland Southeast Asia, possibly around 6000 BCE, and from there spread to Central Asia and Tibet, and then to the Middle East and Europe. Domestication most likely took place in the western Yunnan region of China.[5]

The oldest remains found in China so far date to circa 2600 BCE, while buckwheat pollen found in Japan dates from as early as 4000 BCE. It is the world's highest-elevation domesticate, being cultivated in Yunnan on the edge of the Tibetan Plateau or on the plateau itself. Buckwheat was one of the earliest crops introduced by Europeans to North America. Dispersal around the globe was complete by 2006, when a variety developed in Canada was widely planted in China. In India, buckwheat flour is known as kuttu ka atta and is culturally associated with the Navaratri festival. On the day of this festival, food items made only from buckwheat are consumed.[6]

Cultivation

Buckwheat with flowers, ripe and unripe seeds

Exhibition of Flower Festival, Taiwan

Buckwheat, a short-season crop, does well on low-fertility or acidic soils, but the soil must be well drained. Too much fertilizer, especially nitrogen, reduces yields. In hot climates it can be grown only by sowing late in the season, so that it blooms in cooler weather. The presence of pollinators greatly increases the yield. The nectar from buckwheat flower makes a dark-colored honey. Buckwheat is sometimes used as a green manure, as a plant for erosion control, or as wildlife cover and feed.

The plant has a branching root system with a primary taproot that reaches deeply into moist soil.[7] Buckwheat has triangular seeds and produces a flower that is usually white, although can also be pink or yellow.[8] Buckwheat branches freely, as opposed to tillering or producing suckers, causing a more complete adaption to its environment than other cereal crops.[7] The seed hull density is less than that of water, making the hull easy to remove.[8]

Buckwheat is raised for grain where a short season is available, either because it is used as a second crop in the season, or because the climate is limiting. Buckwheat can be a reliable cover crop in summer to fit a small slot of warm season. It establishes quickly, which suppresses summer weeds.[9] Buckwheat has a growing period of only 10–12 weeks[10] and it can be grown in high latitude or northern areas.[11] It grows 75 to 125 centimetres (30 to 50 inches) tall.[9]

• 
  Field of buckwheat in Bumthang (Bhutan)
• 
  Common buckwheat in flower
• 
  Seed and withered flower of buckwheat
• 
  Buckwheat grain

Buckwheat

Nutritional value per 100 g (3.5 oz)
Energy	1,435 kJ (343 kcal)
Carbohydrates	71.5 g
Dietary fiber	10 g
Fat	3.4 g
Saturated	0.741 g
Monounsaturated	1.04 g
Polyunsaturated omega‑3 omega‑6	1.039 g 0.078 g 0.961 g
Protein	13.25 g
Vitamins	Quantity %DV^†
Thiamine (B1)	9% 0.101 mg
Riboflavin (B2)	35% 0.425 mg
Niacin (B3)	47% 7.02 mg
Pantothenic acid (B5)	25% 1.233 mg
Vitamin B6	16% 0.21 mg
Folate (B9)	8% 30 μg
Vitamin C	0% 0 mg
Minerals	Quantity %DV^†
Calcium	2% 18 mg
Iron	17% 2.2 mg
Magnesium	65% 231 mg
Manganese	62% 1.3 mg
Phosphorus	50% 347 mg
Potassium	10% 460 mg
Sodium	0% 1 mg
Zinc	25% 2.4 mg
Other constituents	Quantity
Copper	1.1 mg
Selenium	8.3 µg
Link to USDA Database entry
Units μg = micrograms • mg = milligrams IU = International units
^†Percentages are roughly approximated using US recommendations for adults.

Composition

Starch

• 71–78% in groats
• 70–91% in different types of flour[12][13][14]
• Starch is 25% amylose and 75% amylopectin.
• Depending on hydrothermal treatment, buckwheat groats contain 7–37% of resistant starch.

Protein

• Crude protein is 18%, with biological values above 90%.[15] This can be explained by a high concentration of all essential amino acids,[16] especially lysine, threonine, tryptophan, and the sulphur-containing amino acids.[17]

Minerals

• Rich in iron (60–100 ppm), zinc (20–30 ppm) and selenium (20–50 ppb)[18][19]

Polyphenols

• 10–200 ppm of rutin, 0.1–2% of tannins[20] and presence of catechin-7-O-glucoside in groats.[21]

Fagopyrin

Buckwheat contains 0.4 to 0.6 mg/g of fagopyrins (at least 6 similar substances)[22][23][24] The fagopyrins have been reported as being located almost exclusively in the cotyledons of the buckwheat herb.[25]

Aromatic compounds

Salicylaldehyde (2-hydroxybenzaldehyde) was identified as a characteristic component of buckwheat aroma.[26] 2,5-dimethyl-4-hydroxy-3(2H)-furanone, (E,E)-2,4-decadienal, phenylacetaldehyde, 2-methoxy-4-vinylphenol, (E)-2-nonenal, decanal and hexanal also 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.[27]

Nutrition

With a 100-gram serving of dry buckwheat providing 1,440 kilojoules (343 kilocalories) of food energy, or 380 kJ (92 kcal) 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 (table). Buckwheat is 72% carbohydrates, including 10% dietary fiber, 3% fat and 13% protein.

Gluten-free

As buckwheat contains no gluten, it may be eaten by people with gluten-related disorders, such as celiac disease, non-celiac gluten sensitivity or dermatitis herpetiformis.[28][29] Nevertheless, buckwheat products may have gluten contamination.[28]

Negative reactions

Cases of severe allergic reactions to buckwheat and buckwheat-containing products have been reported.[30]

Buckwheat contains fluorescent phototoxic fagopyrins.[22] 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 buckwheat sprouts, and particularly flowers or fagopyrin-rich buckwheat extracts.[31] Symptoms of fagopyrism in humans may include skin inflammation in sunlight-exposed areas, cold sensitivity, and tingling or numbness in the hands.[31]

Culinary use

Buckwheat flour

Buckwheat (left), buckwheat flakes (fast cooking) (right), and crispbread made of buckwheat flour.

The fruit is an achene, similar to sunflower seed, with a single seed inside a hard outer hull. The starchy endosperm is white and makes up most or all of buckwheat flour. The seed coat is green or tan, which darkens buckwheat flour. The hull is dark brown or black, and some may be included in buckwheat flour as dark specks. The dark flour is known as blé noir (black wheat) in French, along with the name sarrasin (saracen). Similarly, in Italy, it is known as grano saraceno (saracen grain).[32] The grain can be prepared by simple dehulling, milling into farina, to whole-grain flour or to white flour. The grain can be fractionated into starch, germ and hull for specialized uses.

Buckwheat noodles have been eaten in Tibet and northern China for centuries, where the growing season is too short to raise wheat. A wooden press is used to press the dough into hot boiling water when making buckwheat noodles. Old presses found in Tibet and Shanxi share the same basic design features. The Japanese and Koreans may have learned the making of buckwheat noodles from them.

Buckwheat noodles play a major role in the cuisines of Japan (soba)[33] and Korea (naengmyeon, makguksu and memil guksu). Soba noodles are the subject of deep cultural importance in Japan. The difficulty of making noodles from flour with no gluten has resulted in a traditional art developed around their manufacture by hand.

Noodles also appear in Italy, with pasta di grano saraceno in Apulia region of Southern Italy and pizzoccheri in the Valtellina region of Northern Italy.

Buckwheat groats are commonly used in western Asia and eastern Europe. The porridge was common, and is often considered the definitive peasant dish. It is made from roasted groats that are cooked with broth to a texture similar to rice or bulgur. The dish was taken to America by Ukrainian, Russian, and Polish immigrants who called it kasha, and they mixed it with pasta or used it as a filling for cabbage rolls (stuffed cabbage), knishes, and blintzes; buckwheat prepared in this fashion is thus most commonly called kasha in America. Groats were the most widely used form of buckwheat worldwide during the 20th century, eaten primarily in Estonia, Latvia, Russia, Ukraine, Belarus, and Poland, called grechka in Ukrainian or Russian.

Buckwheat pancakes are eaten in several countries. They are known as buckwheat blinis in Russia, galettes bretonnes in France, ployes in Acadia, poffertjes in the Netherlands, boûketes in the Wallonia region of Belgium, kuttu ki puri in India and kachhyamba in Nepal. Similar pancakes were a common food in American pioneer days.[34] They are light and foamy. The buckwheat flour gives the pancakes an earthy, mildly mushroom-like taste.

Yeasted patties called hrechanyky are made in Ukraine.

A jelly called memilmuk in Korea is made from buckwheat starch

Buckwheat is a permitted sustenance during fasting in several traditions. In India, on Hindu fasting days (Navaratri, Ekadashi, Janmashtami, Maha Shivaratri, etc.), fasting people in northern states of India eat foods made of buckwheat flour. Eating cereals such as wheat or rice is prohibited during such fasting days. While strict Hindus do not even drink water during their fast, others give up cereals and salt and instead eat non-cereal foods such as buckwheat (kuttu). In the Russian Orthodox tradition, it is eaten on the St. Philip fast.[35]

Buckwheat honey is dark, strong and aromatic. Because it does not complement other honeys, it is normally produced as a monofloral honey.

• 
  Soba noodles made from buckwheat flour
• 
  Kuttu ke pakore, a snack made from buckwheat flour, India
• 
  Buckwheat bread (roti) with potato curry and sour curd, Sikkim, India
• 
  Grechka of Russia and Ukraine

Beverages

Black buckwheat tea (黑苦荞茶) produced in Sichuan Province, China

Beer

In recent years, buckwheat has been used as a substitute for other grains in gluten-free beer. Although it is not an actual cereal (being a pseudocereal), buckwheat can be used in the same way as barley to produce a malt that can form the basis of a mash that will brew a beer without gliadin or hordein (together gluten) and therefore can be suitable for coeliacs or others sensitive to certain glycoproteins.[36]

Whisky

Shōchū

Buckwheat shōchū (焼酎) is a Japanese distilled beverage produced since the 16th Century. The taste is milder than barley shōchū.

Tea

Buckwheat tea, known as kuqiao-cha (苦荞茶) in China, memil-cha (메밀차) in Korea and soba-cha (そば茶) in Japan, is a tea made from roasted buckwheat.[37]

Upholstery filling

Buckwheat hulls

Buckwheat hulls are used as filling for a variety of upholstered goods, including pillows and zafu. The hulls are durable and do not insulate or reflect heat as much as synthetic filling. They are sometimes marketed as an alternative natural filling to feathers for those with allergies. However, medical studies to measure the health effects of pillows manufactured with unprocessed and uncleaned hulls concluded that such buckwheat pillows do contain higher levels of a potential allergen that may trigger asthma in susceptible individuals than do new synthetic-filled pillows.[38][39]

Other uses

Buckwheat is used as an ingredient in many "grain free" dog treats and foods. It can also be used in microwaveable heat-retaining slippers and pillows.

Production

Buckwheat production – 2017

Country	Production (tonnes)
Russia	1,524,280
China	1,447,292
Ukraine	180,440
France	127,406
Kazakhstan	120,379
World	3,827,748
Source: FAOSTAT of the United Nations[40]

Historically, the Russian Empire was the world leader in buckwheat production.[41] Growing areas in the Russian Empire were estimated at 2,600,000 hectares (6.5 million acres), followed by those of France at 360,000 hectares (0.9 million acres).[42] In 1970, the Soviet Union grew an estimated 1,800,000 hectares (4.5 million acres) of buckwheat. As of 2016, it remains a key cereal.[43][40]

In the northeastern United States, buckwheat was a common crop in the 18th and 19th centuries. Cultivation declined sharply in the 20th century due to the use of nitrogen fertilizer, to which maize and wheat respond strongly. Over 1,000,000 acres (400,000 ha) were harvested in the United States in 1918. By 1954, that had declined to 61,000 hectares (150,000 acres), and by 1964, the last year annual production statistics were gathered by USDA, only 20,000 hectares (50,000 acres) were grown. However, it may benefit from an "explosion in popularity of so-called ancient grains" reported in the years 2009–2014.[44] In 2017, world production was 3.8 million tonnes, led by Russia with 40% of the world total, followed by China with 38% and Ukraine with 5%.[40]

Biological control

Buckwheat is currently being studied and used as a pollen and nectar source to increase natural predator numbers to control crop pests in New Zealand.[45]

See also

• Eriogonum, a genus of wild North American plants also known as buckwheat
• Buckwheat honey
• List of buckwheat dishes

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