1, protein
The protein component of tartary buckwheat is different from other cereal crops, and its albumin and globulin content is relatively high, accounting for about 46.93% of the total protein content, and the gliadin and glutenin contents are low, which are 3.29% and 15.57%, respectively. Only 1/10 and 1/2 of wheat. The residue protein was 34.32%, which was 12.7 times that of wheat flour 2.7% (Table 3). Differences in the protein components of tartary buckwheat flour and wheat flour have caused differences in the processing characteristics of pasta products. The gluten content of tartary buckwheat flour is very low, similar to legume protein, and the total protein is low due to rice, wheat and corn.
(1) Amino acid: Tartary buckwheat contains 19 kinds of amino acids, not only high in content, but also in good composition. The content of buckwheat amino acids per 100 g is 5.1161 g, which is 50.42% higher than the wheat content (3.401 g); 17.82% higher than the rice content (4.3424 g); 9.95% higher than the corn content (4.653 g); and the ratio of sweet cesium (3.1721) g) 61.28% higher. Histidine and arginine in amino acids are higher in adults and children. Take arginine as an example. The content of buckwheat is 1.014 g per 100 g, which is 2.36 times that of 0.429 g of wheat and 0.745 g of rice. 1.36 times, 2.16 times the content of 0.47 grams of corn, 1.84 times that of the sweet medlar 0.5484 grams.
Of the 8 essential amino acids in humans, the content of buckwheat is higher than that of wheat, rice, corn and sweet buckwheat. In particular, the lysine, which is rich in cereals, is the most indispensable. The content of tartary buckwheat is 2.8 times that of wheat, 1.9 times that of corn, 1.8 times that of rice, and 1.6 times that of sweet glutinous rice. The content of tryptophan, tartary buckwheat is 2.4 times that of corn, 1.71 times that of sweet glutinous rice, 1.6 times that of wheat, and 15% higher than that of rice.
(2) Protein quality: High-quality protein is rich in protein and has a proper ratio of amino acids. At present, the international community often uses “chemical fractions†as the nutritional price of food protein. The higher the chemical score, the more easily the protein can be digested and the higher the quality. The egg protein composition is the optimal amino acid composition close to human needs, with a chemical score of 100. Eggs are the standard for the amino acid composition, and the nutritional prices of tartary buckwheat flour, wheat flour, soybean flour and corn flour are compared (Table 4). .
From Table 4, it can be seen that the 8 kinds of essential amino acids in buckwheat flour are closest to the eggs, and the contents of lysine, phenylalanine and tryptophan are higher, but methionine is slightly lower than that of corn flour, but also for eggs. %, far higher than 40% of wheat flour and corn flour. The chemical composition of tartary buckwheat is 55, which is higher than that of wheat chemical composition 38, rice chemical composition 49, and corn chemical composition 40. Therefore, the protein quality of tartary buckwheat has a higher value in grains.
The European Union's Hans (M.HAAS, 1994) believes that the nutritional value of buckwheat protein is high, and the chemical is divided into 81, which is higher than listed in Table 4. Moreover, there is a new amino acid "yeastine" in the lysine complex.
2, fat
Tartarian buckwheat has a high fat content of 2.1% to 2.8%. It is solid at room temperature and is yellow-green and odorless, which is different from common cereal grains. The components of bitter buckwheat fat are better, containing 9 types of fatty acids, of which the most are highly stable, antioxidant, unsaturated fatty acids, oleic acid and linoleic acid, which account for 87% of the total fatty acids (Table 5).
In addition, stearic acid, myristic acid and unknown acid are also contained in tartary buckwheat. Stearic acid is 2.51% and myristic acid is 0.35%. The fatty acid content of tartary buckwheat differs depending on the origin.
3, starch and dietary fiber
Starch content in tartary buckwheat seeds varies by region and breed. The starch in the buckwheat is similar to the rice starch, but the granules are larger. Compared with the common cereal starch, the buckwheat starch is easily digested and absorbed by the human body after eating.
The tartary buckwheat powder contains 3.4% to 5.2% of dietary fiber, of which the dietary fiber accounts for about 20% to 30% of the total amount of dietary fiber, about 0.68 to 1.56%, and is higher than 8% of the dietary fiber of corn meal. 60.39% is 1.7 times that of wheat flour dietary fiber and 3.5 times that of rice dietary fiber, and the daily standard dietary fiber intake is 20-25 grams. A survey conducted by the comrades of the Yi nationality in Liangshan Prefecture, Sichuan Province, who used the bitter buckwheat as a staple food, showed that consumption of tartary buckwheat reduced serum total cholesterol and LDL cholesterol levels, and it was concluded that it was due to the effect of dietary fiber from tartary buckwheat. Of course, tartary buckwheat dietary fiber also has the function of compounding amino peptides.
According to recent studies, the role of assisted digestion in human nutrition is similar to that of dietary fiber. The results of the starch hydrothermal treatment test of Prof. I. Kreft (S. Slovenia) suggested that buckwheat can be used as a good supplementary diet for people with diabetes, because the hydrolyzed buckwheat starch can be used in comparison with wheat bread to obtain glucose Slow release and relatively high proportion of digestible starch.
4, vitamins
Buckwheat flour contains a lot of vitamins: vitamin B1, vitamin B2, vitamin PP, vitamin P, including B vitamins rich in content. Vitamin B1 and vitamin PP are significantly higher than rice, and vitamin B2 is also 1 to 4 times higher than wheat flour, rice and corn flour, which has the effects of promoting growth, enhancing digestion, and preventing inflammation. Buckwheat also contains vitamin B6, vitamins of tartary buckwheat B6 is approximately 0.02 mg/g.
Buckwheat contains vitamin P (rutin) and vitamin C that are not found in other cereals. Rutin is one of the bioflavonoids. It is a polyphenol derivative and is a rutinglycoside. It and niacin (vitamin PP) both have a role in lowering blood lipids and improving capillary permeability and vascular vulnerability. Vitamin P coexists with vitamin C. Some of the vitamin P content in tartary buckwheat flour is as high as 6% to 7%, while sweet wolfberry contains only about 0.3%, and its content difference is more than 20 times. The vitamin C content in tartary buckwheat is 0.8 to 1.08 mg/g. Vitamin E, which promotes cell regeneration and prevents aging, has a content of 1.347 mg/g.
5, mineral nutrients and trace elements
Bitter buckwheat flour contains a variety of mineral nutrients, which has attracted attention to human functions and food nutrition. It is known that buckwheat is an important source of essential nutrients such as magnesium, potassium, calcium, iron, zinc, copper, and selenium. The high content of magnesium, potassium and iron demonstrates the nutritional and health functions of buckwheat flour.
In bitter buckwheat, magnesium is 4.4 times that of wheat flour and 3.3 times that of rice. Magnesium participates in energy conversion in human cells, regulates myocardial activity and promotes body fibrinolysis, inhibits thrombin generation, lowers serum cholesterol, and prevents arteriosclerosis, hypertension, and heart disease.
The potassium in tartary buckwheat is 2 times that of wheat flour, 2.3 times that of rice, and 1.5 times that of corn flour. Potassium is an important cation that maintains the body's water balance, acid-base balance, and osmotic pressure.
The iron element in bitter buckwheat is very abundant, and its content is 2 to 5 times that of other bulk grains, which can fully guarantee the human body's need for heme iron element and prevent the occurrence of iron deficiency anemia.
The calcium in tartary buckwheat is natural calcium and its content is as high as 0.724%, which is 80 times that of rice. Adding tartary buckwheat powder to food can increase calcium content.
The relationship between zinc and taste disorders is remarkable.
Tartary buckwheat also contains selenium, which has anti-oxidation and immune regulation functions. It can combine with metal in the human body to form an unstable "metal selenoprotein" complex that helps to eliminate toxic substances in the body. Buckwheat is regarded as a precious selenium-rich resource by the National Germplasm Bank. Selenium is an essential trace element determined by the United Nations Health Organization, and it is the only anti-cancer and anti-cancer element identified by the organization. Medical research at home and abroad has confirmed that the lack of selenium in the human body can cause dysfunction of vital organs, and that there are more than 40 diseases in the human body related to dietary deficiency of selenium. The American Cancer Institute medical experts pointed out that the appropriate amount of selenium can prevent almost all cancerous changes. In the United States, the daily dietary intake of selenium per person is 200 μg. Since 71% of regions in China have low levels of selenium or selenium deficiency, the National Institute of Nutrition recommends that the intake of selenium per person per day be 50 μg. At present, the survey results in major cities such as Beijing and Taiyuan are less than 50 μg. The source of selenium in foreign foods is mostly the addition of inorganic selenium to feedstuffs for conversion, and the secondary absorption in the food chain. Selenium in buckwheat is a natural organic selenium, and green plants are used as carriers, so it is very precious and has broad prospects for development.