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BUCKWHEAT
Common buckwheat (Fagopyrum esculentum Moench) is a broad-leafed herbaceous annual. It
belongs to the family Polygonaceae, which is generally referred to as the buckwheat, rhubarb or
sorrel family. However, because its seed structurally and chemically resembles the cereal grains,
buckwheat is usually handled and classed with the cereals. Shown to have originated in the
mountainous regions of southern China, buckwheat is produced in many parts of the world and has
long been an important part of the human diet. Buckwheat has been grown in Canada and the U.S.
for many years.
Buckwheat has a triangular seed, which is covered by a hull (pericarp). The exact shape, size, and
colour of the seed may vary depending on the species and variety. The hull may be a glossy or dull
brown, black or gray. The dehulled buckwheat seed, called the groat, resembles the cereal kernel in
its gross chemical composition and structure. The first layer of the groat is a one-cell thick testa
layer (seed coat), which is light green in color. Under the testa is a one-cell aleurone layer, which
surrounds the starchy endosperm. The inner portion of groat consists of a spermaderm and an
endosperm. A large embryo and two cotyledons extending in the shape of letter AS@ are
embedded in the center of the endosperm.
Buckwheat has gained an excellent reputation for its nutritious qualities in the human diet. Its
renewed popularity stems from its many bioactive components, which have been shown to provide
various health benefits much sought after in natural foods.
SEED COMPOSITION
Buckwheat protein content varies from 13-15 % of the groat. The main protein fraction is globulin,
which represents almost half of all proteins. A characteristic feature of buckwheat proteins protein is
a very low content of prolamins.
Starch is the major carbohydrate in buckwheat, and its amount in the Canadian buckwheat varieties
may vary from 67 to 75 %. Starch granules in the endosperm are polygonal or round in shape with
diameter ranging from 2 to 12 μm. The majority of granules are 6-8 μm in diameter. The dietary
fibre content may vary from 5-11%.
In the whole buckwheat grain the total lipids range from 1.5 - 4%. The highest content is in the
embryo (9.6-19.7%), the endosperm contains 2 - 3% and the hulls 0.4 - 0.7 %. Buckwheat oil
contains 16-20% saturated fatty acids, 30-45% oleic acid and 31-41% of linoleic acid. Palmitic,
oleic, linoleic and linolenic acids account for about 95% of buckwheat total fatty acids.
The ash content of buckwheat varies from 2 - 2.2 %, depending upon the variety. The polyphenolic
compounds of buckwheat were determined at 0.7% in the hulls and 0.8% in the groats. Buckwheat
flour contains various kinds of vitamins, such as B 1, B2, and niacin, at relatively high levels
(Pomeranz, 1983).
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BIOACTIVE COMPONENTS
DIETARY FIBRE, RESISTANT STARCH AND OTHER BIOACTIVE CARBOHYDRATES
Dietary fibre
The amount of total dietary fibre (TDF) in buckwheat may be affected by both genetic and
environmental factors. The major components of TDF, cellulose, non-starch polysaccharides, and
lignins, are concentrated in the cell walls of starchy endosperm, aleurone, seed coat and hull. The
content of TDF in groats may range from 5 to 11% (Joshi and Rana, 1995; Zheng et al, 1998;
Steadman et al, 2001; Izydorczyk et al, 2002). Bran fractions obtained by milling of buckwheat are
especially enriched in dietary fibre (13-16%), but buckwheat flours contain considerably lower
amounts of fibre (1.7-8.5%) (Steadman et al, 2001).
For nutritional purposes, the TDF is classified into soluble- and insoluble dietary fibre.
Insoluble dietary fibre (IDF) decreases transit time in the stomach, small intestine and colon, and
increases faecal mass. It is commonly used as a bulking agent to prevent or treat constipation.
Soluble dietary fibre (SDF), due to its high viscosity, slows gastric emptying, reduces adsorption of
certain nutrients, and increases transit time in the small intestine. SDF contributes to slowing down
of glucose absorption. SDF, and to a lesser extent IDF, are fermented by microflora in the digestive
system to produce short fatty acids, implicated in serum cholesterol and colon cancer reduction. A
considerable portion of buckwheat dietary fibre is soluble. However, relatively little is known about
the composition and properties of SDF in buckwheat. Asano et al (1970) isolated water soluble
non-starch polysaccharides from buckwheat and reported that they consisted of xylose, mannose,
galactose, and glucuronic acid. It was postulated that the main chain of this polysaccharides
consisted of glucuronic acid, mannose, and galactose. More recently, arabinose and glucose
residues have also been identified in water-extractable buckwheat polysaccharides (Izydorczyk et
al, 2002). One of the most important characteristics of buckwheat water soluble non-starch
polysaccharides is their very high molecular weight; as a consequence, they can form very viscous
solutions when dissolved in water.
Resistant starch
The so-called resistant starch – including physically inaccessible starch, native granular starch,
retrograded starch, and chemically and thermally modified starch - is another potential source of
dietary fibre in buckwheat. Resistant starch is a portion of starch and starch degraded products that
escapes enzymatic hydrolysis in small intestine. There are indications that metabolites formed
during fermentation of resistant starch in the large intestine, contribute to the maintenance of colon
health and also have beneficial effects on glucose metabolism. For most healthy adults,
consumption of foods with higher amount of resistant starch is, therefore, advantageous.
Starch is the major component of buckwheat. Although the majority of buckwheat starch is
readily digestible, a small portion (4-7%) resists hydrolysis. Certain treatments of buckwheat starch
or foods containing buckwheat, such as autoclaving/ cooling cycles, extrusion, boiling or baking,
increase the amount of retrograded, nondigestible starch (Skrabanja et al, 1998; Skrabanja and
Kreft, 1998). Consumption of boiled buckwheat groats or bread baked containing 50% of
buckwheat flour induced significantly lower postprandial blood glucose and insulin responses
compared with white wheat bread (Skrabanja et al, 2001).
Fagopyritols
Fagopyritols are specific carbohydrate compounds, first identified in buckwheat and named after the
Latin name of this crop. Fagopyritols are mono-, di-, and trigalactosyl derivatives of D-chiro-inositol
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that accumulate especially in the embryo and the aleurone tissues of buckwheat. Among the plant
sources, buckwheat is the richest in these carbohydrates. It has been reported that the bran milling
fractions may contain 2.6g of fagopyritols per 100g of dry weight, whereas dark and light buckwheat
flours contain 0.7g and 0.3g/100g , respectively. Published literature indicates that D-chiro-inositol
could positively affect the blood glucose level and insulin activity (Fonteles et al, 1999, 2000;
Ortmeyer et al 1993). Work done at the University of Manitoba (Kawa et al, 2003) has shown that
buckwheat extract could be equally efficient in lowering blood glucose level and activating insulin as
synthetic D-chiro-inositol. There is also evidence that D-chiro-inositol can help to control
development of polycystic ovary (Nestler et al, 1999). However, the fate of fagopyritols in the
human digestive system as well as the amount necessary to consume to achieve beneficial effects
remain unknown and require further investigation.
MINERALS
Buckwheat seeds are a good source of many essential minerals (Table). In comparison with other
cereals such as rice, wheat flour or corn, buckwheat contains higher levels of zinc, copper, and
manganese (Ikeda et al, 1998; Steadman et al, 2001). The bio-availability of zinc, copper, and
potassium from buckwheat is especially high. It has been determined that 100g of buckwheat flour
can provide approximately 13-89% of the recommended dietary allowance (RDA) for zinc, copper,
magnesium, and manganese. The concentration of many of the minerals is higher in buckwheat
bran than in the endosperm.
PROTEIN
The protein content in buckwheat flour is the second highest after oat flour, and it is significantly
higher than in rice, wheat, millet, sorghum, and maize. Compared to other cereals, the amino acids
in buckwheat proteins are well balanced and rich in lysine, which is generally recognized as the first
limiting amino acid in wheat and barley. The high-quality buckwheat proteins can complement
cereal and vegetable proteins because of the high levels of lysine as well as arginine (Table 2). The
protein of buckwheat flour has the amino acid score of 100, which is one of the highest amino acid
scores among plant sources. Buckwheat protein consists of 18.2% albumin, 43.3% globulin, 0.8%
prolamin, 22.7% glutelin, and 5.0% other nitrogen residue (Javornik and Kreft, 1984; Ikeda et al,
199l; Ikeda and Asami, 2000). In the absence of gluten type proteins, buckwheat flour can be an
important ingredient in gluten-free diet for people suffering from the celiac disease. Buckwheat
groat and flour can also be an excellent ingredient in bread and cereal formulations.
Despite the balanced amino acid composition, the buckwheat protein digestibility in humans
and in animals is relatively low (Farrell, 1978; Javornik et al, 1981), because of anti-nutritional
factors present in common buckwheat, including protease inhibitors (such as trypsin inhibitors) and
tannins (Ikeda et al 1986, 1991). Trypsin inhibitors in buckwheat seeds are resistant to thermal
processing at elevated temperatures and to acidic conditions (Ikeda et al, 1986, 199l). Germination
of buckwheat seeds significantly reduces the activity of proteases inhibitors, so seedlings and
young buckwheat plants as a food source show improved digestibility and utilization of proteins
(Kreft, 1983).
The low protein digestibility may not be beneficial for growing children and persons with
digestive track problems, since the consumption of insufficiently cooked buckwheat products can
lead to diarrhea. On the other hand, given that obesity is one of the major health problems in North
America, the low buckwheat protein digestibility may not necessary be a negative property. It has
been suggested that soybean trypsin inhibitor can have beneficial effect for people with diabetes by
stimulation of pancreas activity (Ookubo, 1992). In addition, current evidence suggests that
polyphenols in plant foods, especially in red wine, have a beneficial effect on coronary heart
disease (Renaud and de Lorgeril, 1992). "Resistant proteins" such as those in buckwheat have also
beneficial effect on cholesterol level in blood (Kayashita et al, 1996; Iwami, 1998; Tomotake et al,
2000). Carroll et al (1975) reported that ratios of Lys/Arg and Met/Gly are the main factors
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determining the cholestrol lowering properties of proteins. In buckwheat, the ratios of Lys/Arg and
Met/Gly are lower than in the other plant proteins, and nutritional studies have shown that
buckwheat proteins have the highest cholestrol lowering properties among the plant proteins.(Huff
and Carroll, 1975). These amino acids help to regulate the hepatic LDL receptors, and thereby
lowering the serum cholesterol, and indirectly helping to prevent formation of arteriosclerosis.
Moreover, the high content of methionine in the diet negatively affects cholesterol level in serum,
because methionine is the part of homocysteine catabolism which affects the homocysine
transferase. As a consequence the amount of PC (phosphatidylcholine) and PE
(phosphatidylethanolamine), two phosphatides important in cholesterol catabolism as well as in the
clearance of cholesterol in tissues, is affected.
Kayashita et al (1997) reported that the isolate of buckwheat protein (IBP) was more efficient in
cholesterol lowering than soybean protein isolate. The authors also showed that weight gain of IBPfed rats was not negatively affected when compared to the casein-fed rats, suggesting that
buckwheat proteins were sufficiently digested and absorbed to provide adequate amount of amino
acids for growing organisms. The IBP was shown to be more effective in lowering “bad cholesterol”,
LDL and VLDL, than other plant and animal proteins (Saeki et al, 1990).
Buckwheat protein isolate can also be used as a functional food ingredient to treat hypertension,
obesity, as well as constipation. In Japan, a patent describing production of a specific buckwheat
protein has been recently registered. This protein lowers activity of angiotensin converting enzyme
(ACE) and directly controlling hypertension.
Rat feeding experiments showed that high-fat diets and overeating did not affect the body weight
of the animals when buckwheat protein hydrolyzate was included in diet. This protective effect was
much weaker for soybean protein hydrolyzates.
Mitsunaga et al (1986) reported a presence of thiamine-binding protein (TBP) in buckwheat
seeds. After ingestion, this complex is digested by proteases, and thiamine is released and
absorbed. The protein moiety in the TBP complex improves the stability of thiamine during storage
and processing, and enhances its bioavailability.
It is also has been found that buckwheat protein, together with dietary fibre, can ameliorate
constipation (Kayashita et al, 1995). Several epidemiological studies have shown that buckwheat
proteins, like dietary fibre, can suppress the development of colon cancer (Lipkin et al 1999;
Cassidy et al 1994). Hard to digest proteins interact with resistant starch and are the main source of
short chain fatty acids (SCFA), known to positively affect tissues and physiology of colon (Morita et
al 1998; Scheppach et al 1992). Liu et al (2001) utilized buckwheat proteins extract, containing
about 73% buckwheat proteins, to assess its effect on induced colon tumor in rats. It was shown
that dietary buckwheat protein reduced incidence of colonic adenocarcinomas by 47%. Buckwheat
protein also reduced carcinoma cell proliferation and expression in colonic epithelium. The results
clearly suggest that buckwheat proteins have a protective effect against colon carcinogenesis.
FLAVONOIDS
Buckwheat contains many flavonoid compounds, known for their effectiveness in reducing the
blood cholesterol, keeping capillaries and arteries strong and flexible, and assisting in prevention of
high blood pressure (Santos et al, 1999). Rutin, the main buckwheat flavonoid, is a flavonol
glucoside (Fig XX). The flavonoids content and composition in buckwheat seeds is affected by
species, growing phase and growing conditions. Flavonoids content in seeds of the wild buckwheat
(Fagopyrum tataricum) is about 40 mg/g, while in the common buckwwheat (Fagopyrum
esculentum) around 10 mg/g. In flowers, leaves and stems of Fagopyrum tataricum the content of
these compounds can exceed 10% of wet plant weight. Many different flavonoids have been
isolated and identified in buckwheat grain. Rutin, orientin, vitexin, quercetin, isovitexin, quercetrin
and isoorientin are all present in the hull, while groats contain only rutin and small amounts of
isovotexin.
It has been established that rutin can affect the activity of enzyme, angiotensin I, involved in
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controlling blood pressure (Kawakami et al, 1995). Flavonoids can, therefore, be used as effective
drugs to treat some cardiovascular diseases such as arterioscleroses. These compounds also act
as strong antioxidants and can prevent oxidation of DNA and lipoproteins such as LDL, VLDL. Interestingly, flavonoids are transferred from mother to baby across placenta, and further into foetus
brain. These facts suggest that flavonoids are important and essential components for brain
development and for maintenance of the nervous system.
LIGNANS
Lignans are compounds with a dibenzylbutane skeleton, which have been found in many higher
plants (Setchell, 1995). These plant components act in mammalians as hormone-like
phytoestrogens. Although flaxseed is the richest source of plant lignans, containing 75 – 800 times
more that other oilseeds, cereals, legumes, fruits and vegetables, buckwheat also contains a
considerable amount of these compounds (Thompson et al 1991). Secoisolariciresinol diglycoside
(SDG) and matairesinol (MAT) are the main buckwheat lignans. Mammalian lignans are formed by
intestinal microorganisms from plant precursors (Fig X). The concentration of plant lignans acting
as precursors of mammalian lignans is measured by subjecting a particular food ingredient to
fermentation by intestinal microorganism and by measuring the amounts of enterodiol (ED) and
enterolactone (EL) released (Setchell, 1995). In animals, the excretion of ED and EL is measured in
the urine (Rickard and Thompson, 2000). Fig Y shows urinary excretion of ED and EL when
different plant components were included in the diet. Buckwheat provided the third highest amount
of excreted lignans among many cereals. Lignans have been shown to reduce mammary tumor size
by more than 50% and tumor number by 37% in carcinogen treated rats (Rickard and Thompson,
2000; Setchell, 1995). Furthermore, it has been suggested that lignans have antimiotic,
antiestrogenic, antiviral, antibacterial, antifungal, and antioxidant properties (Rickard &Thompson,
2000; Thompson et al, 1996; Thompson et al, 1995; Setchell et al, 1995).
FOOD USES
Buckwheat grain is milled into flour or dehulled to produce groats. Two types of milling are used to
produce flour. One is similar to wheat milling in which the grain is milled into flour. The nutritive
components, rheological properties and volatile components of the flour produced by this method
have been reported by (Kusano and Miyshita 1973).
The second type of milling involves milling the dehulled buckwheat groat. Buckwheat grain
is first hydrothermally treated and then dehulled. Different conditions and equipment are used for
groat production, and the effects of these treatments on the final products have been reported by
Pomeranz (1983).
Buckwheat flour and groats are used for a wide variety of dishes. The flour is mixed with
wheat flour for the production of buckwheat noodles called ‘soba noodles’ in Japan. The buckwheat
flour content ranges from 50 to 80% depending on the type of noodle produced.
The groats are utilized in many dishes in through out the world. In Asia they are consumed as
noodles, dumplings and as unleavened chapattis. In Europe, Kasha is used in dishes ranging from
pilafs to mixtures with meat. In North America, the main use has been in pancakes; however,
utilization of buckwheat has been increasing in the form of noodles and various ethnic dishes.
Buckwheat is also used in pastries and as a meat extender.
Buckwheat Promotion
THIS MATERIAL WAS PREPARED BY:
Canadian Grains Commission
Website: http://grainscanada.gc.ca
Marta Izydorczyk
Program Manager, Barley Research
Grain Research Laboratory
Canadian Grains Commission
1404-303 Main Street
Winnipeg, MB R3C 3G8
Phone: (204) 983-1300
Fax: (204) 983-0724
Email: [email protected]
University of Manitoba
Website: http://umanitoba.ca
Roman Przybylski
Associate Professor
University of Manitoba
Dept of Human Nutritional Sciences
190 Dysart Rd.
Winnipeg, MB R3T 2N2
Phone: (204) 474-8657
Fax: (204) 474-7593
Email: [email protected]
Kade Research Ltd.
Website: http://kaderesearch.com
Clayton Campbell
135-13 Street
Morden, MB R6M 1E9
Phone: 204-822-7235
Fax: 204-822-5960
Email: [email protected]
6
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REFERENCES:
Asano, K., Morita, M., Fujimaki, M. (1970). Studies on the non-starchy polysaccharides of the
endosperm of buckwheat. Agr. Biol. Chem. 34: 1522-1529.
Carroll, K.K. and Hamilton, (1975) R. J. Food Sci. 40:18-22
Carroll, K.K. and Kurowska, E.M. (1995) Soy consumption and cholesterol reduction: review of
animal and human studies. J. Nutr. 125:594S-597S
Cassidy, A., Bingham, S.A. and Cummings, J.H. (1994). Starch intake and colorectal cancer risk:
and international comparison. Br. J. Cancer 69:937-942.
Farrell, D.L. (1978). A nutritional evaluation of buckwheat (Fagopyrum esculantum). Anim. Feed
Sci. Technol. 3:95-108.
Fonteles, M.C., Almeida, M.Q. and Larner, J. (2000) Antihyperglycemic effects of 3-O-methyl-Dchiro-inositol and D-chiro-inositol associated with manganese in streptozotocin diabetec rats. Horm.
Metab. Res. 32:129-132.
Friis, S.U. (1988) Enzyme-linked immunosorbent assay for quantitation of cereal proteins toxic in
celiac disease. Clinica Chimica Acta 178:261-270.
Huff, M.W. and Carroll, K.K. (1980) J. Lipid Res. 21:546-558.
Ikeda, K. (2002) Buckwheat:composition, chemistry and processing. Advances in Food and
Nutrition Research 44:395-434.
Ikeda, K., Arai, R. and Kreft, I. (1998). A molecular basis for the textural characteristics of
buckwheat products. In: Advances in Buckwheat Research, Eds. C. Campbell and R. Przybylski,
Winnipeg, Manitoba, vol. III, pp. 57-60.
Ikeda, S. and Asami, Y. (2000). Mechanical characteristics of buckwheat noodles. Fagopyrum
17:67-72.
Ikeda, S., Edotani, M., and Naito, S. (1990). Zinc in buckwheat. Fagopyrum 10: 51-55.
Ikeda, S., Matsui, N., Shimizu, T. and Murakami, T. (1991) Zinc in cereals. In: Cereals International.
Eds. D.J. Martin and C.W. Wrigley, Royal Australian Chem. Inst., Parkville, pp. 248-250.
Ikeda, S., Yamashita, Y., and Murakami, T. (1995). Minerals in buckwheat. Current Adv.
Buckwheat Res. pp. 789-792.
Ikeda, K., Oku, M. Kusano, T. and Yasumoto, K. (1986) Inhibitory potency of plant antinutrients
towards the in vitro digestibility of buckwheat protein. J. Food Sci. 51:1527-1530.
Iwami, K. (1998). Antitumor effects of resistant proteins in soybean. Food Style 21:44-46.
Javornik, B. and Kreft, I. (1984). Characterization of buckwheat proteins. Fagopyrum 4:30-38.
Javornik, B., Eggum, B.O. and Kreft, I. (1981) Studies on protein fractions and protein quality of
buckwheat. Genetika 13:115-118.
Kayashita, J., Shimaoka, I. and Nakajoh, M. (1995). Hypocholesterolemic effect of buckwheat
protein extract in rats fed cholesterol enriched diets. Nutr. Res. 15:691-698.
Kayashita, J., Shimaoka, I., Nakajoh, M., Yamazaki, M. and Kato, N. (1997). Consumption of
buckwheat protein lowers plasma cholesterol and raises fecal neutral sterols in cholesterol-fed rats
because of its low digestibility. J. Nutr. 127:1395-1400.
Kayashita, J., Shimaoka, I., Yamazaki, M. and Kato, N. (1995). Buckwheat protein extract
ameliorates atropine-induced constipation in rats. Curr. Adv. Buckwheat Res. 2:941-946.
Kayashita, J., Shimaoka, I., Nakajoh, M. and Kato, N. (1996). Feeding of buckwheat protein extract
reduces hepatic triglycerides concentration, adopose tissu weight, and hepatic lipogenesis in rats.
J. Nutr. Biochem. 7:555-559.
Kayashita, J., Shimaoka, I., Nakajoh, M., Kishida, N. and Kato, N. (1999). Consumption of a
buckwheat protein extract retards 7,12-dimethylbenz(α)anthracene-induced mammary
carcenogenesis in rats. Biosci. Bitechnol. Biochem. 63:1837-1839.
Kawa, J., Przybylski, R. and Taylor, C. (2003). Effect of buckwheat extract on blood glucose and
insuline. J. Metab. Res. (Accepted for publication).
Kawakami, A., Inbe, T., Kayahara, H. and Horii, A. (1995) Preparation of enzymatic hydrolysates of
buckwheat globulin and their angiotensin I converting enzyme inhibitory activities. In: Current
Advances in Buckwheat Research, Eds. T. Matano and A. Ujihara, Shinshu University Press, Ina,
Buckwheat Promotion
8
pp. 927-934
Kreft, I. (1983) Buckwheat breeding perspectives. In: Buckwheat Research. Eds: T. Nagatomo and
T. Adachi, Kuroda-Toshado Printing, Miyazaki, pp. 3-12.
Kreft, I., Skrabanja, V., Ikeda, S., Ikeda, K. and Bonafaccioa, G. (1998)) Buckwheat nutritional value
and technological properties. In: Alternative Getreiderohstoffe-Technologie und
ErnahrungischeBedeutung. Universitat fur Bodenkultur, Vienna, pp.44-51.
Kreft, S., Knapp, M. and Kreft, I. (1999) Extraction of rutin from buckwheat seeds and determination
by capillary electrophoresis. J. Agric. Food Chem. 47:4649-4652.
Kurzer, M.S., Slavin, J.L. and Adlercreutz, H. (1995). Flaxseed, lignans and sex hormones. In:
Flaxseed in Human Nutrition. Eds. S.C. Cunnane and L.U. Thompson, AOCS Press, Champaign,
1995, pp.136-144.
Lipkin, M., Reddy, B., Newmark, H. and Lamprecht, S.A. (1999). Dietary fractors in human
colorectal cancer. Annu. Rev. Nutr. 19:545-586.
Liu, Z., Ishikawa, W., Huang, X., Tomotake, H., Kayashita, J., Watanabe, H. and Kato, N. (2001). A
buckwheat protein product suppresses 1,2-dimethylhydrazine-induced colon carcinogenesis in rats
by reduced cell proliferation. J. Nutr. 131:1850-1853.
Mitsunaga, T., Matsuda, M., Shimizu, M. and Iwashima, A. (1986). Isolation and properties of a
thiamine-binding protein from buckwheat seed. Cereal Chem 63:332-335.
Morita, T., Kasaoka, S., Ohhashi, A. Ikai, M. Numasaki, Y. and Kiriyama, S. (1998). Resistant
proteins alter cecal short-chain fatty acid profiles in rats fed high amylose cornstarch. J. Nutr.
128:1156-1164.
Nestler, J.E., Jakubowicz, D.J., Reamer, P., Gunn, R.D. and Allan, G. (1999) Ovulatory and
metabolic effects of D-chiro-inositol in the polycystic ovary syndrome. New Eng. J. Med. 340:13141320.
Ohsawa, R. and Tsutsumi, T. (1995) Improvement of rutin content in buckwheat flour. In: Current
Advances in Buckwheat Research, Eds. T. Matano and A. Ujihara, Shinshu University Press, Ina,
pp. 365-372.
Ookubo, K. (1992) Nutrition and functionality of soybean. In: Science of Soybean. Eds: F.Yamauchi
and K. Ookubo, Asakura-Shoten Press, Tokyo, pp. 57-75.
Ortmeyer, H.K., Huang, L.C., Zhang, L., Hansen, B.C. and Larner, J. (1993) Chiroinositol deficiency
and insu;in resistance. II. Acute effects of D-chiro-inositol administration in streptozotocin-diabetic
rats, normal rats given a glucose load, and spontaneously insulin-resitant Rhesus monkeys.
Endocrynology 132:646-651.
Park, C.H., Kim, Y.B., Choi, Y.S., Heo, K., Kim, S.L., Lee, K.C., Chang, K.J. and Lee, K.Y. (2000).
Rutin content in food products processed from groats, leaves and flowers of buckwheat.
Fagopyrum 17:63-66.
Pomeranz, Y. (1983). Buckwheat: structure, composition and utilization. CRC Crit. Rev. Food
Chem. 19:213-258.
Pomeranz, Y. and Robbins, G. S. (1972) Amino acid composition of buckwheat. J. Agric. Food
Chem. 20: 270-274.
Renaud, S. and de Lorgeril (1992) Wine, alcohol, platelets, and the French paradox for coronary
heart disease. Lancet 339:1523-1526.
Rickard, S.E. and Thompson, L.U. (2000). Urinary composition and posprandial blood changes in
H-secoisolariciresinol diglycoside metabolites in rats do not differ between acute and chronic SDG
treatments. J. Nutr. 130:2299-2305.
Saeki, S., Kananchi, O. and Kiriyama, S. (1990). Some metabolic aspects of the
hypocholesterolemic effect of soybean protein in rats fed a cholesterol-free diet. J. Nutr.Sci.
Viaminol. 36:125S-131S.
Santos, K.F.R., Oliveira, T.T., Nagem, T.J., Pinto, A.S. and Oliveira, M.G.A. (1999) Hypolipidaemic
effects of narigenin, rutin, nicotinic acid and their associations. Pharma. Res. 40:493-496.
Scheppach, W., Sommer, H., Kirchner, T., Pagneli, G.H. and Bartram, P. (1992).Effect of butyrate
enemas on the colonic mucosa in distal ulcerative colitis.Gastroenterology 103:51-56.
Setchell, K.D.R. (1995) Discovery and potential clinical importance of mammalian lignans. In:
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Flaxseed in Human Nutrition. Eds. S.C. Cunnane and L.U. Thompson, AOCS Press, Champaign,
1995, pp. 82-98.
Skerritt, J.H.. (1986). Molecular comparison of alcohol-soluble wheat and buckwheat proteins.
Cereal Chem. 63:365-369.
Skrabanja, V. and Kreft, I.. (1998). Resistant starch formation following autoclaving of buckwheat
(Fagopyrum esculentum Moech) groats. An in vitro study. J. Agric. Food Chem. 46: 2020-2023.
Skrabanja, V., Laerke, H.N., and Kreft, I. (1998). Effects of hydrothermal processing of buckwheat
(Fagopyrum esculentum Moech) groats on starch enzymatic availability in vitro and in vivo in rats. J.
Cereal. Sci. 28: 209-214.
Skrabanja, V., Liljeberg Elmsttahl, H.G.M., Kreft, I., and Bjorck, M.E. (2001). Nutritional properties of
starch in buckwheat products: Studies in vitro and in vivo. J. Agric. Food Chem. 49: 490-496.
Steadman, K.J., Burgoon, M.S., Lewis, B.A., Edwardson, S.E., and Obendorf, R.L. 2001. Minerals,
phytic acid, tannin and rutin in buckwheat seed milling fractions. J. Sci. Food Agric.81:1094-1100.
Steadman, K.J., Burgoon, M.S., Schuster, R.L., Lewis, B.A., Edwardson, S.E., and Obendorf, R.L.
(2000) Fagopyritols, D-chiro-inositol, and other soluble carbohydrates in buckwheat seed milling
fractions. J. Agric. Food Chem. 48: 2843-2847.
Tomotake, H., Shimaoka, I., Katashita, J., Yokoyama, F., Nakajoh, M. and Kato, M. (2000)
Abuckwheat protein product suppresses gallstone formation and plasma cholesterol more strongly
than soy protein isolate in hamster. J. Nutr. 130:1670-1674.
Thompson, L.U. (1995). Flaxseed, lignans and cancer. In: Flaxseed in Human Nutrition. Eds. S.C.
Cunnane and L.U. Thompson, AOCS Press, Champaign, 1995, pp. 219-236.
Thompson, L.U., Robb, P., Serraino, M. and Cheung, F. (1991). Mammalian lignan production from
various foods. Nutr Cancer. 16: 43-52
Thompson, L. U., Seidl, M. M., Rickard, S. E., Orcheson, L. J. and Fong, H. H. (1996)
Antitumorigenic effect of a mammalian lignan precursor from flaxseed. Nutr Cancer. 26:159-165
Yoshi, B.D. and Rana, R.S. (1995). Buckwheat ((Fagopyrum esculentum). In: Cereals and
Pseudocereals. J.T. Williams (ed.). Chapman & Hall, London.
Zheng, G., Sosulski, F., and Tyler, R. (1988). Wet-milling, composition and functional properties of
starch and protein isolated from buckwheat groats. Food Res. Int. 30: 493-502.
Buckwheat Promotion
COMPANIES OFFERING BUCKWHEAT PRODUCTS
Minn-Dak Growers Ltd.
Grand Forks, ND 5820803276
The Birkett Mills
263 Main, Penn Yan, NY 14527
Sobaya
201 Miner St., Cowansville, Quebec J2K 3H1
Port Royal Mills
240 Industrial Parkway South, Aura, ON. L4G 3V6
Arrowhead Mills
734 Franklin Ave, #444, Garden City, NY 11530
Bouchard Family Farm
RR#2 Box 2690, Fort Kent, Maine 04743
Bob’s Red Mill Natural Foods
5209 SE International Way, Milwaukee, OR 97222
Brownville Mills
P.O. Box 145, Brownsville, NB 68321
Purity Foods
2871 W. Jolly Road, Okemos, MI 48864
Clic Import Export
2025 Boul. Fortin, Laval, QB H7S 1P4
Mountain Peoples Warehouse
22-30th Street NE, Suite 102, Auburn WA 98002
Ontario Natural Foods Co-op
70 Fima Cresent, Etibicoke, ON, M8W 4V9
Great Eastern Sun
92 McIntosh Road, Ashville, NC
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BUCKWHEAT USE IN FOOD RECIPES
BUCKWHEAT PILAF
2 Tbsp. butter or margarine
1 cup uncooked, whole buckwheat
1/3cup currants
1/4 tsp. oregano
Salt and pepper to taste
3 1/2 cups chicken stock or
3 1/2 cups boiling water and 3 chicken
Bouillon cubes
1 Tbsp. grated orange rind
1/3 cup finely chopped pecans, optional
2 Tbsp. chopped parsley
Melt butter in large saucepan. Add buckwheat. Stir well. Add chicken stock, cover and cook for
approx. 20 minutes or until all the liquid is absorbed. Add rest of ingredients except parsley.
Transfer to greased 2 1/2 quart casserole dish and bake at 350 0F for 30 to 40 minutes. Garnish
with parsley. Serves 6
BUCKWHEAT PUDDING
1cup buckwheat groats
2 cups water
1 tsp. cinnamon
1cup raisins
2 cup sunflower seeds
Bring 2 cup water to a boil. Add 1cup buckwheat or millet. Bring to a boil. Stir once. Add raisins and
seeds and cinnamon. Turn heat to low, cook uncovered for 20 minutes or until grain is cooked.
Serve hot with yogurt and honey.
VEGETARIAN SOBA NOODLE SUSHI
1/2 pound soba noodles - blanched al dente
1/4 cup scallions, green part only finely chopped
2 Tbsp. light soy sauce
1 Tbsp. rice wine vinegar
Wasabi oil
1/4 cup pickled ginger - finely chopped
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10 sheets nori
1 cucumber, peeled and finely julienned
1 red bell pepper, julienned
1 yellow bell pepper, julienned
In a large mixing bowl, combine soba noodles, spring onions (scallions), soy sauce, rice wine
vinegar, wasabi oil, and pickled ginger. Taste for seasoning. On a sushi mat, place one sheet of
nori, shiny side down. On the bottom third of the nori, place a thin layer of the noodle mixture. Place
some cucumber and peppers on top. Roll tightly. Moisten the top edge of the nori with water to seal
the sushi roll closed.
Serves 8 to 10
Buckwheat Promotion
Table 1. Content of Minerals in Buckwheat and Milling Fractions.
Minerals
Whole groats
mg/kg
Flour
mg/kg
Bran
mg/kg
K
5650
5003
14163
P
4900
4167
13533
Mg
2676
2530
59910
Ca
197
300
333
Fe
30.3
34.0
60.4
Zn
29.2
28.3
72.6
Mn
16.4
18.0
46.2
B
6.7
6.6
24.1
Cu
7.1
7.0
10.4
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Table 2. Comparison of Essential Amino Acid Contribution in Buckwheat, Cereals, and Egg.
(g/100g protein).
Buckwheat
Barley
Wheat
Corn
Egg1
Lysine
5.1
3.7
2.5
2.8
6.0
Methionine
1.9
1.8
1.8
2.4
3.8
Cystine
2.2
2.3
1.8
2.2
2.4
Threonine
3.5
3.6
2.8
3.9
4.3
Valine
4.7
5.3
4.5
5.0
7.2
Isoleucine
3.5
3.7
3.4
3.8
5.9
Leucine
6.1
7.1
6.8
10.5
8.4
Phenylalanine
4.2
4.9
4.4
4.5
6.1
Histidine
2.2
2.2
2.3
2.4
2.2
Tryptophan
1.6
1.1
1.0
0.6
1.5
TD (%)
79.9
84.3
92.4
93.2
99
BV (%)
93.1
76.3
62.5
64.3
100
NPU (%)
74.4
64.3
57.8
59.9
94
UP (%)
9.1
7.3
7.3
6.0
12.2
Amino Acid
Abbreviations: TD – True Protein Digestibility; BV – Biological Value (Based on amino acid
composition); NPU – Net Protein Utilization; UP – Utilizable Protein (Protein x NPU/100); 1 –
For whole egg.
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OH
OH
OH
OH
O
OH
OH
OH
OH
O
O
H
H
O
OH
Quercetin
O
OH
H
OH
OH
OH
OH
O
O
H
O
OH
H
H
H
H
CH3
Quercetrin
Buckwheat flavonoids
O
H
OH
H
H
H
HO
O
H
H
OH
H
OH
H
O
CH2OH
O
OH
OH
Rutin
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Plant Lignans
O
H3CO
H3CO
OR
O
OR
HO
Secoisolariciresinol
Diglycoside (SDG)
OCH3
OH
HO
Matairesinol
Bacterial
Fermentation
OCH3
OH
Bacterial
Fermentation
O
HO
HO
OH
O
OH
Bacterial
Fermentation
OH
Enterodiol (ED)
OH
Enterolactone (EL)
Mammalian Lignans
Formation of mammalian lignans and their plant precursors.
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r
Co n O
il
rn
M
W
ea
he
l
at
Fl
W
he ou
r
at
G
W
he erm
a
So t Br
a
y
So bea n
yb
n
ea Oi
l
n
Ba Me
r le
a
yM l
O ea
at
l
M
M
e
Bu ille
a
ck t M l
w
he eal
at
Ry Mea
e
l
M
Fl
ea
ax
l
s
Fl
ax eed
se
ed Oil
M
ea
l
Co
Urinary Excretion (g/g diet)
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21
18
15
12
9
6
3
0
Fig X.Total excretion of mammalian lignans in the urine of rats after diet
supplementation with various foods.
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