Buckwheat is a whole or crushed buckwheat endosperm, freed from shells. To obtain high-quality buckwheat, the peculiarity of the microstructure of the starchy part of the endosperm of the grain is of great technological importance, since it is it that is the basis of varietal cereals. The fact is that the inside of the cells is occupied by starch granules and protein layers, but if, for example, in wheat and barley protein layers are well developed, and starch particles differ in size from 1 to 50 microns, then in buckwheat (and rice) starch granules differ less in size (from 2 to 10 microns), and there is very little protein between them. Therefore, the endosperm of buckwheat is fragile and fragile, which complicates the production of whole cereals – part of the grain is crushed under mechanical action and comes out in the form of chipped core particles.
Two main types of cereals are produced from buckwheat grain – buckwheat kernel and buckwheat prodel. Kernels are cereals made from whole grains, the prodel consists of crushed grains.
After passing the sieves of the sifting, a mixture of core, thread, husk and flour is obtained. The core and the thread are separated by passing through sieves measuring 1.6-1.7 x 20 mm. The flour is separated from the mixture and taken by the passage of a sieve No. 08, and the husk is separated from the thread, sifting it into two fractions using a sieve No. 1,4. Each of the two fractions is then screened on aspiration columns.
Buckwheat unground is produced from steamed grain without shells with a minimum content of impurities. It has a stronger, but faster-digestible core and is of the highest grade. Also, whole buckwheat groats, depending on the content of impurities and a good-quality kernel, are divided into 1st and 2nd grades. Buckwheat has no grade, but, like unground, it can be with a short cooking period due to the hydrothermal treatment of the grain.
In cereal production technology, hydrothermal treatment is of decisive importance. The more severe the mode of steaming the grain, the more actively the decomposition and loss of the content of vitamins and minerals occur, the chemical composition of buckwheat changes. Such cereals are dark in color and quickly boil during cooking.
In the 50s of the 20th century, green buckwheat was sold everywhere in the USSR. She began to acquire a “fried” look after the advice of Nikita Khrushchev, who “noticed” such a feature in buckwheat during his visit to the United States. The most complete composition of buckwheat nutrients is preserved in raw green buckwheat. Processed using a special technology, this type of cereal is the leader in the rating of healthy cereals.
The requirements for finished cereals are high. Buckwheat is an important dietary product, and fast-digesting 1st grade kernel grown without the use of pesticides is used for the production of baby food.
First of all, fresh buckwheat should have a color corresponding to its presentation – from cream with a greenish tint for ordinary cereals to brown with various shades for fast-cooking buckwheat kernel. During storage, the color may change, but at the same time it must always be uniform. It is determined visually in diffused daylight or artificial light, sprinkling the cereal in a continuous layer on black glass or paper. The grains should have a clear rounded shape and a smooth surface.
The smell inherent in buckwheat should be weak, without signs of mustiness and mold. Extraneous odors arising from an undesirable commercial proximity are also unacceptable. To check the quality of cereals based on the smell, a 20 g serving. can be placed in a porcelain container, covered with glass and placed in a water bath, heated for 5 minutes.
The taste of the cereal can be determined by chewing about 1 g. grains: fresh cereal is slightly bland or slightly sweetish, sourish and rancid shades indicate the process of its deterioration.
The increased moisture content of cereals negatively affects the nutritional value and composition of buckwheat, cereals with high moisture are stored less and spoil faster. The maximum permissible moisture content for buckwheat is 14%. The moisture level can be determined by drying the crushed cereal sample at 130 C for 40 minutes, and then comparing it with the mass of the original sample, expressing the difference as a percentage.
The content of trash impurities (fruit casings, broken kernels) is determined by sifting a sample (up to 100 grams) through a sieve for flour or broken kernels. In the residues of impurities, their mass is expressed as a percentage of the original mass. Impurities worsen the presentation and reduce the price of buckwheat, negatively affect the safety of cereals, its nutritional and taste qualities. If the content of impurities is more than the norm, the cereals are transferred to a lower grade or considered non-standard.
In order to control pests, at the first stage, the degree of infestation of the grains is determined. To do this, it is necessary to sift 1 kg of cereals on sieves, and then carefully calculate the number of live pests and determine their type.
The nutritional value of buckwheat is checked on the basis of chemical analysis. For this, in laboratory conditions, not only the general composition of buckwheat nutrients is determined, but also their balance, the peculiarity of starch properties, the ratio of proteins, their amino acid usefulness, the group and fatty acid composition of lipids, the amount of mineral elements, the content of biologically active substances, etc.
Methods for monitoring and assessing the quality of buckwheat are regulated by performance standards. Important indicators include sensory (appearance, color, taste, smell) and laboratory (moisture, amount of a complete core, presence of impurities, size, evenness, presence of metal-magnetic impurities, torment, unshelled grains, pests, etc.). In addition, production laboratories must determine the hygienic state of cereals – the presence of radionuclides, and cereals for baby food – the content of heavy metals and residual pesticides.
When determining the quality of cereals, it is important to inspect the entire batch, including its container, correct marking and filling out accompanying documents.
Also, the culinary merits of the studied cereal are subject to control. They are assessed by taste, color, smell, structure and digestibility of buckwheat porridge. Buckwheat, produced from steamed grain, has less specificity of buckwheat taste and smell. A high concentration of protein makes the consistency of the porridge better, and the presence of a large amount of fiber, polysaccharides (pentosans) and water-soluble substances worsen it.