Something lately I have been increasingly unpleasantly surprised by seedling seedlings. I do not know for what reason the seed coat does not fall from the leaves of many sprouts. This phenomenon is very unpleasant, because if it is not removed, the seedlings will lag behind in development and may even die. How to help seeds fling off their shell?
Usually, the remaining seed coat signals that the shoots are weak. But do not rush to reject crops, since a similar phenomenon occurs with small crops. So, tomatoes, peppers and eggplant when sowing should be buried only 1 cm. Deeper is undesirable, and smaller - too. If planted smaller, then many seed shells will not subside after emergence. Such plants can be helped to get rid of the seed coat. To do this, create high humidity conditions and strengthen the plants by watering them with a Kornevin solution.
Advice from the "Economy"
You can’t remove the peel manually, as this will inevitably damage the cotyledon leaves. Not to mention the fact that in the seed coat the leaf blade is not hardened and after exposure may suffer from sunburn.
But if the seeds are old, then there can be especially many seeds that are not released from the shell. There is no point in saving them, since weak sprouts will not yield a high yield. Such sprouts just need to be removed.
Another reason for such non-standard seedlings is a loose or dry substrate. It is usually loose due to the high content of peat. Therefore, when making the mixture, add at least a third of the garden or turf land. She will give the desired density. If the land is small, and peat predominates, then the sprouts, not meeting resistance, will carry the seed coat out to the sun.
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In the groove, the seed coat and the pigment band join together, forming a common shell around the endosperm and embryo. When ripening grain, both parts of this shell are filled with an oily substance or a cork-type substance.
Most researchers believe that this substance is a cork type.
The pigment layer is filled with pigment only in red grain wheat. According to Krause, there is a skin-like layer and an outer lignified layer around the cork substance of each cell. The latter is also mentioned in the works of Bradbury et al.
The seed shells of Pony and Trubile wheat have been studied in detail in some detail; they are completely similar in structure and composition. The seminal membrane is firmly connected to either the transverse or tubular cells on the outside and the nucleicular epidermis on the inside. Three layers can be distinguished in the seed coat: a thick outer cuticle, a “colored layer” containing pigment, and a very thin inner cuticle. However, the last layer can in some places be so closely connected to the color layer that it becomes indistinguishable. A fourth, especially thin layer of hyaline substance was discovered in Trubile wheat; believe that it was formed from swollen external pectin containing cell walls of the outer layer of the seminal membrane. A similar layer was also observed in Poony wheat, where, by histochemical analysis, it gave a positive result for the content of pectin and fiber. The hyaline layer (soluble in sulfuric acid) is located between the outer cuticle and the color layer.
Both cuticles give a positive reaction when tested for suberin or cutin. More extensive microchemical analyzes indicate that the seed coat is cutinized.
The color layer in Ponya wheat, in contrast to this layer in Trubile wheat, gives a weak positive reaction when analyzed for tannins. In wheat grain, the color layer consists of two layers of cells, which, as the grain ripens, change and shrink. The cells of these two layers intersect each other at an angle of less than 45 °. According to Percival, these cells have a size of 100-150; according to Fogl, their width does not exceed 9-12 centners.
The seed coat of white wheat differs from the seed coat of red wheat. In white wheat, both compressed layers of the cells that make up the central part of the seed coat are fiber and not corky. They contain almost no or very little pigment, depending on the variety. Only the cells located in the groove have few scattered bast inclusions. When the seed coat is treated with sulfuric acid, the cells of these two layers dissolve and two films remain: the outer cuticle, which resembles the cuticle of red wheat, and the thin inner film, which has no structure.
Both the outer cuticle and the seed coat as a whole in different parts of the grain have different thicknesses. The outermost layer of the seminal membrane has the greatest thickness in the groove, at the top of the grain (at its sharp end) and in the region from the ejaculatory to the base of the groove, and the smallest - above the embryo. The thickness of the outer cuticle (erroneously described as a seed coat) in Pacific Northwest wheat is 1.5-3.5. In Ponium wheat, the average thickness of the outer cuticle is 2–4 and the thickness of the seed coat is about 5–8. The outer cuticle, like the entire seed coat, is thicker near the pigment edge in the groove, at the top of the grain and at the base of the grain near the lower part of the embryo. In the area of \u200b\u200bthe vas deferens, above the protruding basal part of the embryo, the seed coat of red wheat is so modified that water and microorganisms can quite easily penetrate into the grain through it. In addition, mold and moisture can find access to the vas deferens through the spongy parenchymal tissue of the pericarp at the site of attachment of the grain to the mother plant. The structure of the seed coat in the ejaculatory region has been studied in detail in red and white wheat.
Corn cereals consists of flower films covering the grain outside, the fruit and seed membranes, the aleuron layer, the endosperm (mealy core) and the germ (Fig. 8.1, 8.2).
Flower films and fruit and seed membranes make up 4 ... 6% of the grain mass, contain a lot of fiber and mineral salts, vitamins. When processing grain, flower films and shells are removed, since they are not absorbed by the human body.
The aleurone layer accounts for 5 ... 7% of the grain mass, is rich in fats, proteins, mineral salts, vitamins B, B 2, PP, but it contains a lot of fiber, which reduces the nutritional value of grain and makes it difficult to absorb nutrients. Therefore, when processing grain, the aleurone layer is removed. Fig. 8.1. Lengthwise cut
Fig. 8.2. Cross section
wheat (under the microscope): 1 - a beard; 2 ... 4 - fruit and seed membranes; 5 - aleuron layer; 6 - endosperm; 7 - the germ
plot of wheat grain [under the microscope):
1 - fruit shell;
2 - seed coat;
3 - aleuron layer;
4 - endosperm
The endosperm is the main nutrient of the grain and averages from 51% (in oats) to 83% (in wheat) of the grain mass. It contains starch (36 ... 59%), proteins (7 ... 12%), sugar (2 ... 3%), fats (1%), a small amount of fiber and mineral salts. Therefore, the digestibility of products consisting of endosperm (premium flour, rice, etc.) is high, but the biological value is relatively low due to the low content of vitamins and mineral salts.
The consistency of the endosperm can be powdery, glassy or semi-glassy, \u200b\u200bwhich depends on the different content of proteins and starch. A grain containing a lot of starch is opaque, powdery, and containing a lot of protein is dense, solid, transparent. In processing, vitreous grain gives a high yield of premium flour with better properties and more suitable for pasta production. The embryo, which makes up 7 ... 9% of the grain mass, contains proteins, fats, sugar, mineral salts, vitamins, enzymes, fiber, and absolutely no starch. Despite the high value of the embryo, when processing grain into flour and cereal, they strive to remove it, since the fat contained in it is easily oxidized and causes rancidity of the product. For food purposes, only an embryo of wheat grains (for vitamin E) and corn (for oil) is used.
| Krupa______________________________
Groats - one of the important food products, which after flour takes the second place. From year to year, cereal production and its assortment are increasing.
The chemical composition and energy value of cereals. Groats have a high nutritional value. So, it contains biologically active substances - essential amino acids, vitamins, mineral salts. Croup is widely used in cooking for preparing a variety of dishes, and in the food industry - for concentrates and canned food. The nutritional value of cereals depends on its chemical composition.
The main component of all types of cereals is starch(47.4 ... 73.7%). The highest starch content is characterized by cereal from rice, wheat, and corn. The composition of cereals includes squirrels(7 ... 23%), the largest protein in cereals from legumes is the most valuable cereal from buckwheat, rice, and oats in terms of the content of essential amino acids. Fat in cereals 0.5 ... 6.9%. In cereals containing a lot of fat (oatmeal, cereal from millet, buckwheat), slight bitterness is allowed during storage, since cereal fat is unstable during storage. Fiber in cereals from 0.2% (in semolina) to 2.8% (in oat); fiber reduces the quality of cereals and its digestibility. In addition, cereals are available vitamins (B lr B 2, B 6, PP, carotene, folic acid, biotin, pantothenic acid); mineral salts (potassium, phosphorus, sodium, calcium, magnesium, iron, zinc, manganese, copper, iodine, cobalt, etc.). The value of cereals also depends on its color, appearance and culinary properties, which are characterized by taste, texture, smell, digestibility and increase in volume.
Energy value of 100 g of cereal 322 ... 356 kcal.
Cereal production. To obtain cereals, the grain is cleaned of impurities. During the production of cereals from oats, buckwheat, corn, peas, the embryo, which makes up 7 ... 9% of the grain weight, contains proteins, fats, sugar, mineral salts, vitamins, enzymes, fiber, and absolutely no starch. Despite the high value of the embryo, when processing grain into flour and cereal, they strive to remove it, since the fat contained in it is easily oxidized and causes rancidity of the product. For food purposes, only an embryo of wheat grains (for vitamin E) and corn (for oil) is used. can apply hydrothermal treatment (steam under pressure) and drying. Such processing facilitates the crushing of grain, increases storage stability and shortens the cooking time (fast-growing cereals).
Grain sorting by size provides better crushing and crushing of grain. Hulling (peeling) is the removal of flowering films (millet, rice, barley, oats), fruit shells (buckwheat, wheat) and seed (peas). Sorting after peeling - separation of husk (unshelled broken kernels) increases the yield of cereals, improves its appearance. For a more thorough removal of the fruit and seed membranes, partially the aileron layer and the germ, the grits are ground. Grits such as peas are polished, that is, shells and an aleuron layer are additionally removed to give the grits a smooth polished surface.
Polishing and grinding processes improve the appearance of cereals, its culinary properties, but reduce the value of cereals, because part of the proteins, vitamins, and minerals are removed along with fiber.
Then the cereal is cleaned by sifting out the flour, sifting out the beaten grains and sorted, and the barley, wheat, corn groats are sorted on sieves according to the size corresponding to the number of cereals, after which the cereal is packaged.
An assortment of cereals. Polished millet - This is the core of millet, freed from flowering films and partly from fruit, seed membranes and the germ. By quality, it is divided into the highest, grade 1, 2 and 3 grades. Depending on the variety, the color of millet is light or bright yellow, the consistency is from mealy to glassy. Vitreous millet with a large kernel of bright yellow color is considered the best. Proteins of millet are not valuable enough, so it is better to use it in combination with cottage cheese, milk, eggs and meat. In cooking, millet is used for cereals, casseroles, soups, puddings, minced meat. It is boiled for 40 ... 50 minutes, increases in volume by 6 ... 7 times.
Buckwheat. Buckwheat is divided into kernels and passed.
The kernel is the whole kernels of unpaired buckwheat, separated from the fruit shells, cream-colored with a yellowish or greenish tint.
The fast-boiling egg is produced from steamed buckwheat grain with the removal of fruit shells, brown color with shades. The core and the core of fast-boiling are divided by quality into 1st, 2nd and 3rd grades.
The genus GI ate on split kernels of unpaired and steamed buckwheat (made quick-cooking). Did iiti varieties not subdivided.
In cooking, buckwheat is used to make cereals, soups and minced meat. Viscous cereals, cutlets and meatballs are prepared from prodel. The kernel is boiled for 40 ... 50 minutes, and the fast-cooking one - 15 ... 20 minutes, increasing in volume by 5 ... 6 times.
Oat groats. Several types of cereals are produced from cereal oats.
Uncrushed oat groats - a product that has been steamed, peeled and ground. The color of the cereal is grayish yellow in various shades. The quality of cereals is of the highest, 1st, 2nd grades.
Flattened oat groats have a corrugated surface and white-gray color. They get it as a result of crushing oat uncrushed groats, previously steamed. By quality, it is divided into the highest, 1st grade and 2nd grade.
From oats also produce flakes "Hercules", petal, "Extra".
Hercules is obtained from uncrushed steamed oatmeal of the highest grade by additional steaming, flattening on smooth rollers and drying. Flakes have a thickness of 0.5 ... 0.7 mm, they quickly boil (no more than 20 minutes) and are well absorbed. Petal flakes are also prepared from premium oat groats, additionally subjected to grinding, sorting by size, steaming and conditioning; these flakes are valued higher than Hercules, they are better absorbed and digested faster - in 10 minutes. Extra flakes are obtained from 1st class oats. Depending on the cooking time, they are divided into No. 1 - obtained from whole oatmeal, No. 2 - small flakes from cut cereals, No. 3 - small flakes quickly cooked, prepared from cut cereals. All flakes are white with a cream tint to yellow.
Fiber is large oat kernels crushed into flour, pre-soaked, steamed and dried. Color from light cream to cream, plain, the texture is soft. Use it without heat treatment in combination with hot or cold milk, with yogurt, kefir.
Oatmeal is used for making mashed soups, viscous cereals, milk and mucous soups, casseroles. Cooked oatmeal 60 ... 80 min (except cereal). Porridge from them is obtained mucous, dense.
Rice groats. By the method of processing and quality, rice groats are divided into types and varieties.
Rice polished is polished rice grains processed in grinders, in which flower films, fruit and seed shells, most of the aleuron layer and the germ are completely removed. The surface is rough.
Polished rice is produced by extra, higher, 1, 2 and 3 grades.
Polished crushed rice - these are crushed rice kernels formed during the production of polished rice, additionally processed on grinders. Crushed rice is not divided into varieties.
The quality, composition and consumer benefits of rice cereal depend on the properties of rice grain.
High taste properties are characterized by rice I, II and III types. Type IV rice is inferior in quality. Rice V, VI and VII types of medium quality. „
Compared to other cereals, rice has less fiber, starch grains have a good moisture capacity, so rice dishes (soups, puddings, cereals, meatballs) are well absorbed by the body, they are widely used in diet food. The cooking time of rice is 40 ... 50 min, while it increases in volume by 5 ... 7 times.
Semolina. Obtained in mills with varietal rhombus of wheat into flour.
Particles with a diameter of 1 ... 1.5 mm are pure endosperm. By the type of wheat coming to the grinding, semolina is divided into brands M, T and MT.
Semolina is made from soft wheat. It is opaque, powdery, white or cream-colored; it is used in baby food for the preparation of liquid and viscous cereals, dumplings, muffins and mousses.
Grade semolina of grade T is obtained from durum wheat. It is translucent, ribbed, cream or yellowish; it is used for cooking soups and minced meat.
MT brand cereal is obtained from soft wheat mixed with 20% durum. It is opaque, powdery, white, with the presence of a translucent nibs, creamy yellow; use grits for cutlets and casseroles.
Semolina has high energy value, but is poor in vitamins and minerals, quickly digested - in 10 ... 15 minutes.
Wheat groats. By the method of processing durum wheat and the size of grains it is subdivided into numbers and species, for example, Poltava - four numbers and a species called Artek.
"Poltava groats" No. 1 - whole wheat grain, freed from the embryo and partially from the fruit and seed membranes, polished, elongated, with rounded ends; No. 2 - particles of crushed grain, completely freed from the embryo and partially from the fruit and seed membranes, polished, with rounded ends, oval in shape; Nos. 3 and 4 — particles of crushed grain of various sizes, completely freed from the embryo and partially from the fruit and seed membranes, round, polished.
Krupa “Artek” is a finely divided grain of wheat with a diameter of 1 ... 1.5 mm.
The color of wheat groats of all types and numbers is yellow, the content of a benign kernel is at least 99.2%, the taste and smell are inherent in cereals, without extraneous smacks and smells. Apply wheat cereals for cooking soups, cereals, puddings, casseroles.
Barley groats. Pearl barley is obtained from cereal barley by removing flower films, partially fruit and seed membranes and the germ with mandatory grinding and polishing, and barley by crushing and grinding barley kernels of various sizes.
Pearl barley is divided into five numbers along the length of the grains: No. 1 (3.5 ... 3 mm) and 2 (3 ... 2.5 mm) - of an elongated shape and well-ground kernels with rounded ends; they are used for soups; No. 3 (2.5 ... 2 mm), 4 (2 ... 1.5 mm) and 5 (1.5 ... 0.5 mm) are spherical nuclei, color from white to yellowish, sometimes with a greenish tint, they make porridge, meatballs and zrazy.
Barley groats are produced in three numbers No. 1 (2.5 ... 2 mm), 2 (2 ... 1.5 mm), 3 (1.5 ... 0.5 mm). These are crushed barley kernels of polyhedral irregular shape. Croup contains more fiber and minerals than pearl barley, worse absorbed by the body. Use this grits for cooking porridge, meatballs.
Corn grits. Depending on the size of the grains and the processing method, the following types of cereals are produced: polished corn - five grains of siliceous and semi-toothless corn, the color of the cereal is white or yellow with shades; large corn - for the production of cereals and air grains; small corn - for crispy sticks.
Corn flakes (cornflakes) - in the form of thin petals from corn, which is soaked, crushed, and the germ is separated. Coarse corn grits are boiled in malt sweet syrup, flattened in the form of petals and fried. Get the product ready for use.
Air corn grains are prepared from refined corn grain by “exploding” it in special pressurized apparatuses, where the grain is boiled in “its own steam”, and then due to a sharp pressure drop, vapor and air expand inside the grain. The volume of corn grain increases 5 ... 6 times, acquires a cotton-like soft structure, ready for use with milk, cocoa, etc.
The disadvantages of corn cereals are considered to be the content of defective proteins and low culinary advantage - long cooking (about an hour) of them cereals and rapid aging, since proteins swell slowly and do not soften well, and gelatinized starch quickly gives off water. Krupa is used for cooking soups.
Bean groats. Ground peas are produced from food peas; according to the processing method, ground peas are whole and chopped.
Both peas are subdivided in quality into 1st and 2nd grades.
The whole peas are polished - these are undivided round cotyledons with a smooth surface, impurities of chopped peas in it no more than 5%, humidity 15%, peas of a different color are allowed no more than 7%.
Ground chipped peas are divided cotyledons with a smooth or rough surface and with rounded ribs. The color of the whole pea is yellow or green.
Use peas for cooking first and second courses, as well as a side dish.
Beans Food beans by color and shape are divided into types - white, oval or elongated beans, colored monophonic (green, yellow, brown, red in different shades) of round or oval shape and colored motley (light and dark). White beans are superior in quality to color.
Plate lentils. It has the shape of a biconvex lens. The following three types of large-seed plate lentils are considered the best in cooking: dark green, light green, heterogeneous color.
In composition, lentils are close to peas, but are distinguished by a high content of proteins and starch. Lentils are used for soups, side dishes and main dishes.
Cooking time for lentils is 45 ... 60 minutes, peas - 1 ... 1.5 hours, beans - 1 ... 2 hours, while legumes grow in volume by 3 ... 4 times.
Other types of cereals. These include “P io nersky”, “3 d ers”, “Sportion” and combined cereals - “I’m yo yu yu”, “Strong "," Navy ". These cereals have increased nutritional value. They are made from rice, minced or oat crushed cereals, crushed into flour, with the addition of skimmed milk powder, sugar, soy flour. The resulting mixture is steamed, formed into cereals, dried and packaged in cardboard (paper) boxes. Such cereals are well boiled and convenient for preparing various dishes, especially for baby and diet food. Guaranteed shelf life of 10 months.
The industry is developing the production of quick-digesting cereals: pearl-barley No. 1, 2, 3, Poltava wheat No. 1, 2 and 3, millet, rice and pea kernels. This cereal is additionally moistened, steamed, some flattened and dried. The composition and property of the cereal does not differ from ordinary ones, but it cooks faster - in 10 ... 20 minutes.
Sago. This is a cereal consisting of grains of oleisterized starch. Distinguish between natural sago, which is prepared from starch extracted from the core of the trunks of the saga palm or roots of the shrub root, and artificial, obtained from corn or potato starch. Depending on the grain size, artificial sago is divided into two types: small with a diameter of 1.5 ... 2.1 mm and large with a diameter of 2.1 ... 3.1 mm.
Depending on the quality, sago are divided into the highest and 1st grades. Use it for cooking cereals, soups, casseroles, puddings and minced meat.
Grain quality requirements. The color, taste and smell of cereals should be characteristic of this type of cereal, without extraneous odors and flavors.
Mass fraction of moisture in the cereal is not more than 12 ... 15.5%. The main indicator by which cereals are divided into varieties is the content of a benign kernel. For example, polished extra, premium grade rice has a benign core of at least 99.7%, 1st grade - 99.4%, 2nd grade - 99.1%, 3rd grade - 99%.
Obligatory requirements for the quality of the whole cereal, ensuring its safety for the life and health of the population, are the presence of mineral impurities - not more than 0.05% (sand, pebbles, earth particles, slag), organic impurities - not more than 0.05% (flower films, particles of stems), seeds of plants (wild-growing, cultivated), harmful impurities not more than 0.05% (smut, ergot, sophora tailed, colorful yarn), metal-magnetic impurities not more than 3 mg per 1 kg of product.
Infection of cereals with pests of grain stocks is not allowed.
Cereals with a musty, moldy odor and the smell of rancid cereal fat are considered unsuitable for food.
Packaging and storage of cereals. Cereals come to catering enterprises in fabric bags with a capacity of 50 ... 60 kg or in paper bags, packs, boxes with a capacity of 0.5 ... 1 kg, packed in boxes with a capacity of 15 kg.
Store cereals in dry, well-ventilated warehouses at a temperature of 12 ... 17 ° C and relative humidity of 70% up to 10 days.
The implementation of the protective function leaves a specific imprint on the structure of integumentary tissues, especially the outer shells of seeds - fruit and seed. These tissues consist of powerful and solid fibrous tissue composed of elongated thick-walled cells, usually dead, lacking intracellular contents. Due to the specific location of the cells and their shape, the tissue is sometimes called palisade (Fig. 3).
Fig. 3. The structure of the tissues of the fruit and seed membranes of oilseeds:a - the fruit shell of sunflower: 1 - the epidermis (peel) with a cutinized layer, 2 - the hypodermis, 3 - the shell layer (phytomelan), 4 - sclerenchyma (palisade, or fibrous tissue), 5 - parenchymal rows, 6 - thin-walled parenchyma, 7 - seminal membrane, 8 - endosperm, 9 - external epidermis, 10 - spongy parenchyma (our data); b - castor seed shell: 1 - peel, 2 - parenchymal layer, 3 - thin-walled palisade layer, 4 - thick-walled palisade layer; c - flax seed coat: 1 - cutinized layer, 2 - skin, 3 - thick-walled parenchyma, 4 - fibrous layer (palisade tissue), 5 - transverse cells, 6 - pigment layer, 7 - endosperm (according to V. A. Nassonov) .
Many oil-bearing fruits and seeds are covered with a thin film (coating) of wax or cutin, which helps to increase the protective and insulating properties of integumentary tissues. The integumentary tissues of many fruits and seeds form hairs that enhance the protective functions of the tissue or contribute to a better distribution of seeds. In cotton seeds, for example, epidermal hairs - cotton - reach a length of 70 mm. Sometimes an even coarser protective tissue is formed in the integumentary tissues - cork. The cells of this tissue die off and consist only of thick walls that surround cavities filled with air or resinous substances. The walls of the cells are saturated with suberin, water and air tight, the tissue is strong and elastic.
If mature seeds retain a fruit membrane that does not deteriorate during harvesting, then the seed membrane may consist of cells whose structure is similar to that of the cells of the main tissue - the embryo or endosperm. For example, in sunflower seed coat is a thin film consisting of two tissues: external - fringed and internal - endosperm.
If, after ripening, the fruit membranes are not preserved in the seeds, then the seed membrane is usually strong, and the cells that make it up are similar in structure to the cells of the fruit membrane. In some cases, the seed coat can grow together with oil-containing tissues of the kernel (for example, in flax), and even with the destruction of seeds, this connection is not completely broken. More often, the seed coat only comes into contact with the kernel (in soybean, mustard, cotton, castor oil).
Technology for the production of grain products, flour, cereals.
The production of grain raw materials, as well as products of its processing: cereals, flour, breakfast cereals, food concentrates of first and second courses based on cereal products and animal feed, occupies one of the leading places in the agri-food complex.
The development of the food industry in Ukraine is characterized by the intensification of technological processes of all processing industries. This process is accompanied by concentration and specialization of production based on more advanced technology, equipping enterprises with modern equipment.
Application for food production of various machines and devices connects technical disciplines with food production technology. Therefore, specialists involved in the design or operation of equipment of food processing enterprises need to know the basics of food production technology.
Grain structure
The grain of all cereal crops has approximately the same structure, which can be considered with wheat grain as an example. Its shape is oval. Its convex side is called the back, the opposite - the abdomen. A notch (groove) passes along the abdomen. At the sharp end of the grain there is a prolapse (beard), and at the blunt end there is a germ.
A longitudinal section of wheat grain: 1 - crest, 2-4 - fruit and seed membranes; 5 - aleuron layer; 6- endosperm; 7- shield; 8 - embryo.
Fruit shell protects the grain and covers it outside. Fruit membranes contain a lot of fiber, mineral salts. The body does not absorb fruit membranes.
Seed coat accounts for 6-8% of the mass of grain. It is richer in minerals, nitrogenous substances, sugars, and they have less fiber. The pigment layer of the seed coat gives the grain an appropriate color.
Fruit and seed casings worsen the presentation of flour and cereals, nutritional value, texture, therefore, upon receipt of flour and cereals they are separated.
The inner part of the grain - endosperm, or powdery kernel, accounts for 80-82% of the grain weight, is its most valuable part for the production of flour and cereals.
It consists mainly of starch and protein, contains a small amount of sugar, fat, vitamins and very few minerals.
Embryo averages 3% of the grain mass. It contains a lot of proteins, fats, sugars, vitamins, enzymes.
External (aleuron) layeradjacent to the seed coat - up to 13.5% of the grain weight, contains a large amount of proteins, fats, sugars, minerals, vitamins, but these valuable substances are almost not absorbed, since the cells in which they are located are covered with thick membranes of fiber.When grinding grain, the aleurone layer is separated along with the shells.
Legume seeds consist of an embryo and two cotyledons, have virtually no endosperm. The seed is protected by a dense seed coat.
Sunflower and soybean seeds consist mainly of an embryo with one row of endosperm cells, protected by the seed coat.
The chemical composition of the grain
The composition of the individual parts of the grain depends on:
Botanical traits (species, varieties, breeding varieties),
Growth conditions (climatic conditions, soil composition, fertilizers, watering),
Degree of ripening, etc.
The average chemical composition of grains of various types may vary in the content of protein, carbohydrates, fats, minerals, vitamins.
Waterin dry grain is 12-14% and is in a bound state. It does not activate biochemical processes, and the grain is stable during storage.
Carbohydrates cereal grains contain up to 70%, legumes - up to 55% (in soybeans up to 26%), in sunflower - 16%.
The composition of carbohydrates includes: starch (up to 40-55% of the grain weight), sugar, fiber, hemicellulose.
Digestible carbohydrates - starch and simple sugars - are the main sources of energy for the human body. Non-digestible carbohydrates or ballast substances - fiber and hemicellulose - improve peristalsis and normalize the intestinal microflora.
Squirrels make up from 10 to 14% in cereal grains and 20-35% in legumes.
In terms of amino acid composition, rye proteins are richer than wheat, with many essential amino acids, especially lysine, and have great nutritional value. Pea protein lacks about a third of methionine and cystine.
Wheat flour proteins absorb water well and swell to form a dough. The main part of the test is gluten.
Gluten is called elastic, elastic and bound jelly remaining after washing a piece of dough from starch and particles of grain shells in the water after washing. Gluten consists mainly of proteins - gliadin and glutenin.
Gluten connects the dough into an elastic mass and is characterized by elasticity, elasticity, extensibility, cohesion.
Gluten of good quality is white sometimes with a yellowish or grayish tint. After deformation, it quickly regains its shape, does not stick to hands.
Lipids in the grain of cereals and legumes they make up from 2 to 6.2%, in soybean - 17%.
The composition of fats consists mostly of unsaturated fatty acids, as well as phospholipids (lecithins, cephalins), which are necessary for a person to renew cells and intracellular structures. However, unsaturated fatty acids are easily oxidized, leading to rancid flour and cereal storage.
Water Soluble B Vitamins concentrate in the shell of the grain, so in the flour of high varieties of these vitamins are few. Many B vitamins in legumes.
Enzymes play the role of regulators of biochemical processes, have the ability to accelerate the course of various biochemical metabolic reactions . Of those contained in the grain are very important -
Proteolytic (proteinases), they act on protein substances,
Amylases - α, β-amylases that break down starch,
Lipases - hydrolyzing fat.
Minerals make up 2-5% of the dry matter of the grain and form ash after burning a grain sample.
The composition of the grain includes:
Macronutrients with a content of several to hundredths of a percent: P, Mg, K, Na, Fe, S, Al, Si, Ca;
Trace elements with contents from thousandths to hundredths of a percent: Mn, B, Sr, Cu, Zn, Ba, Ti, Li, I, Br, Mo, Co;
- micronutrients with a content of up to millionths of a percent: Se, Cd, Hg, Ag, Au, Ra.
Minerals are concentrated in the shell of the grain and during normal grinding are mostly removed.
Pigmentsconstitute a group of coloring substances.
The yellow endosperm of the grain is given by carotenoids, unsaturated hydrocarbons or their acid derivatives.
The coloring of the shells is due to flavonoids - yellow phenolic substances (for example, glycosides).