Wheat in agriculture divided into real or breeding, wild or spelt. Both wild and bred wheat are classified by type into durum and soft. Each breed and subspecies of cereals has its own characteristics, chemical and physical properties of the grain. To streamline the indicators of grain crops in Russia, state standards have been developed for each type of cereal.

Real wheat is resilient and flexible, with a strong stem and ear. When threshed, the flower films are separated from the grain quickly. Spelled is characterized by a fragile and brittle straw, dense structure: when threshed, the films are almost inseparable from the seed.

Both bred and wild varieties are classified according to grain quality, including English and Polish wheat, into hard and soft wheat. Hard grain differs from soft grain in chemical composition, biochemical properties and baking qualities.

GOSTs for wheat seeds, developed back in the USSR, are constantly being revised and supplemented in order to correspond to real time and follow the constant work to improve the culture. All changes and innovations are published in the annual index of national standards.

Current GOST R52554-2006 “Wheat. Specifications” gives recommendations on its cultivation.

The main provisions of the standard also describe internal types that differ in natural characteristics. The values ​​of wheat classes are necessary for the determination and approval of technological and nutritional, commercial properties. By changing indicators, such as vitreousness or seed moisture, crop subtypes are determined.

Grain classification

Wheat classes are determined by the worst value after sorting, cleaning and drying the seeds. GOST 93-53-90 provides for a commodity classification of a crop, which is characterized by flour-grinding and baking properties.

For soft varieties, there is also a conditional 6th class. Separation by quality and chemical composition is necessary to improve the production of flour and cereals with a good yield. The classification of wheat in Russia provides for 5 classes for durum varieties.

Soft wheat of the highest and first two classes is called strong and is used for baking bread varieties, to improve flour from weak grains. If the indicators of wheat of the 3rd class give out a gluten content above 23%, then it is used to produce high-quality flour without impurities of stronger varieties. Grade 4 wheat is a cereal that is weak in chemical and baking properties. Flour from such grain necessarily requires the addition of strong varieties. Grade 5 wheat - grain intended for non-food purposes (livestock feed, feed production or processing for glucose, etc.).

Class 2-4 durum wheat is defined as soft class 4 if the amount of admixture of seeds of other plants (including cereals) is above 15%.

Since 1995, Grade 4 grain has been divided into 2 additional groups. This is due to poor yields and a crisis in agriculture. The first group includes seeds with a gluten level from 21 to 33%. Such seeds are used for the production of varietal flour. The second group includes wheat seeds with gluten from 18 to 21%, which are used as fodder or for the production of flour with the addition of strong varieties.

Durum wheat is more used for the production of pasta, desserts and elite breads. Soft - for bread and bakery, confectionery products.

Wheat types

The existing 5 types of wheat differ:

• Color: depending on the type, the seeds are from white to brown-red;
• botanical subtype.

The first 4 species have their own subspecies, including wheat seeds, similar in shade and vitreousness. The classification of grain according to natural characteristics of types and subtypes also distinguishes 5 groups. Group 1 includes soft spring wheat with vitreousness:

• More than 75% - the grain has a dark red middle;
• From 60 to 75% - the middle of the seeds is red;
• Up to 60 from 40% - the middle of the grain is pale red;
• Below 40% - the middle with a yellow tint.

Group 2 of spring wheat includes 2 subtypes:

1. With vitreousness over 70% and rich amber consistency;
2. With amber and light amber consistency. The vitreous index is not regulated.

Group 3 includes all subtypes of soft red winter wheat and the same characteristics as for group 1 apply. Group 4 includes winter varieties with white fruit shells. Group 5 - only hard winter varieties.

In cases where harvesting is carried out ahead of time or if stored improperly, the grain may change color. This phenomenon is called "discoloration of mealy grains".

Grain quality of wheat

In accordance with current GOST 13586.3-83 Sampling of grain to assess the quality of grain is made from the batch during loading or unloading. Healthy wheat grain without mold, traces of fungus and spores, bacteria. It is solid, without chips, cracks and other mechanical damage. It has a flat and smooth surface of the color corresponding to the type. The smell of wheat seeds is rich and bready, without sour, bitter or chemical notes.

The main indicator characterizing the classiness of wheat grain and its nutritional value is protein. Its content depends on the breed and type of cereal, it can reach up to 23%. Protein is richer in hard varieties, and seeds of the 1st class contain the largest amount of protein. The minimum is set at 14%. For grade 5, the minimum protein content is 10%.

In the bakery industry, gluten content is of great importance. It determines the elasticity, elasticity and taste of bread. To control gluten, its indicator is used mass fraction in grain. The minimum quantity is set only for the first 3 classes of wheat. For soft varieties of the first class, the gluten content is not less than 32%, the 2nd class of wheat must have at least 28%, the 3rd - at least 23%. Indicators for hard varieties: 28%, 25% and 22% respectively. For grade 5 wheat, both hard and soft breeds, the gluten level must be at least 18%.

The vitreousness of the grain affects the flour-grinding qualities: the yield of premium flour and its grain-forming ability. According to the results of the analysis of the consistency of the endosperm, wheat is classified as vitreous, partially vitreous or farinaceous. The definition of vitreousness is detailed in GOST 10987-76. It contains a list of the equipment required for analysis, the exact sample weight is 50 g, the maximum moisture content is 17%, and two methods for carrying out the procedure. Vitreousness is determined either using a diaphanoscope or manually.

For the reference color of each class, the color of the healthy grain of the type or subtype is used. For the first four classes, discoloration of the first degree is permissible under certain conditions. Feed wheat does not have a regulated seed color parameter.

To determine the size of seeds, a standard is used - the mass of 1000 grains. The indicator depends on the size of the seeds, the stage of maturity and maturity. The mass is calculated according to GOST 10842-89.

The moisture index is related to the chemical composition: the less water in the seeds, the higher the concentration of nutrients and the nutritional value of the product. Grain moisture is determined by GOST 29027. The method for determining grain moisture consists of sampling, dehydration and weighing before and after drying. Additionally, moisture meters can be used. These devices are able to determine the moisture content of the seed in the range from 5 to 40%, and the error is less than 1.5%.

The composition of the grain batch

Wheat seeds of each variety may contain impurities of other varietal species. For the first 4 classes of spring crops of soft varieties, the level of impurities is set to not more than 5%, for the 5th class - up to 15%. For hard spring varieties, the established maximum is 5%. If there are more biological plant contaminants, then wheat is classified as a mixture of cereal species and the percentage composition of each cereal is indicated.

The main seeds of the first 4 classes include whole and damaged grains, as well as some broken or corroded. The nature and extent of grain damage does not affect its relation to cultural or weed impurities. In wheat of the 5th class, the presence of legume seeds that are not included in the group of weed impurities is permissible.

Weed mix includes:

• Mineral admixture: lumps of earth, pebbles;
• Plant particles, seeds;
• Darkened and empty wheat grains;
• Spores of smut, smut, ergot, etc.;
• Fusarium seeds.

Permissible percentage of weed impurities for the first 4 classes - no more than 2. For the fifth class - no more than 5%. Does not allow infection of wheat with insects, except for mites (but not higher than the second degree). By sanitary requirements the presence of even a minimum amount of pesticides in wheat raw materials is unacceptable. Control was established for hexachlorocyclohexane, DDT and their metabolites. For each batch, a certificate must be issued with the obligatory indication of the content of not only toxins, but also mycotoxins and pesticides. Permissible amount of pesticides according to GOST 13586.1: DDT metabolites - up to 0.05 mg/kg, HCCH isomers - up to 0.2 mg/kg.

Storage and transportation

During transportation and storage, the condition of the cereal is taken into account:

• Humidity: dryness up to 14%, average dryness - up to 15.5%, wet - up to 17%, wet - over 17%;
• Weed impurity: pure grain - less than 1% impurities, medium purity - up to 3% impurities, more than 3% - clogged grain.

During storage, it is necessary to provide wheat seeds with protection from pests - ticks, insects, mice, birds. For pest control, a complex of physical and mechanical measures is used: heat treatment of raw materials, the use of chemicals, sound or mechanical traps. Pests of granaries, in accordance with sanitary standards, are detected by mechanical damage to grain, droppings, smell and other traces of vital activity. Damaged grain does not meet the standard and must be disposed of.

The quality of wheat depends on chemical parameters and type, affects the baking properties of flour and the subsequent taste of the finished product.

Determination of the composition of wheat seeds occurs in the laboratory using a special analysis. According to its results, the party is assigned to one of the classes. Acceptance rules and methods of subsequent processing are regulated by federal law and are spelled out in the relevant GOST.

The condition of the wheat received for storage or processing must meet the standards: the seeds must not contain harmful impurities and infection with fungi and bacteria. Color, smell, weight and mass fraction of moisture must be within the limits allowed by the standard. If, according to one of the criteria, the grain does not meet the standard, the sample is sent for an additional check, based on the results of which a decision is made on disposal or admission to processing.

Introduction

Today, consumers pay a lot of attention to the quality of their products. The successful promotion of the product in the consumer market and its ability to compete with similar products depend on the quality. The topic of this work was not chosen by chance, since grain, cereals and flour are essential products, and the quality of products manufactured by the confectionery, baking, pasta and catering industries depends on their quality.

The purpose of this work is to study the quality indicators of grain, cereals, flour and find out the standards and norms that these indicators must comply with.

The tasks of the work are to present the theoretical material on the classification of the characteristics of the quality of grain, cereals and flour, on some methods for determining the quality of these products.

It should be noted that the paper describes only the main indicators of the quality of grain, flour and cereals. In practice, during the examination of the quality of these products, a much larger number of features are evaluated, which cannot be described in detail in the volume of one work.

Corn. Main indicators of grain quality

Corn is a raw material for the flour and cereal industry.

Distinguish grain for food and fodder purposes. According to the intended purpose, food grain is usually divided into flour, cereal, technical (brewing, starch, fatty oil, alcohol, etc.). The grain of the same crop can be used for different purposes. For example, corn is a raw material for the production of flour, cereals, starch, canned food, vegetable oil, but also a fodder crop.

The use of cereals depends on their chemical composition. According to the chemical composition, cereals are usually divided into three groups:

rich in starch - cereals. The content of starch is 70-80%, proteins - 10-15%. These include wheat, rye, barley, oats, rice, millet, corn (false cereal), buckwheat family;

rich in protein - legumes. The content of carbohydrates is 50-55%, proteins - 25-40%;

rich in fats - oilseeds. The content of fats is 25-35%, proteins - 20-40%.

Cultivated crops according to botanical characteristics (fruit, inflorescence, stem, root) belong to three families: cereals, buckwheat, and legumes.

The quality of grain and products of its processing is regulated by standards. In GOSTs for grain harvested for all crops, a classification is established - division into types, subtypes according to various characteristics: color, size, shape, etc., as well as basic (calculated) and restrictive norms. It is indicated that this crop is considered the main grain, weed and grain impurities.

Basic quality standards are those standards that grain must meet in order to receive the full purchase price for it. These include moisture (14-15%), grain and weed land (11 3%), nature - depending on the crop and growing area. If the grain is better than the basic quality standards in terms of moisture and contamination, then the supplier is charged a cash bonus. For moisture and weediness of grain that are excessive against the basic quality standards, appropriate discounts are made on the price and weight of grain.

Restrictive quality standards are the maximum allowable lower than the basic requirements for grain, under which it can be accepted with a certain price adjustment.

Depending on the quality, the grain of any crop is divided into classes. The division is based on the typical composition, organoleptic indicators, the content of impurities and special quality indicators. Separate, more stringent requirements are set for grain intended for the production of baby food.

To characterize the quality of grain, the following indicators are used: general (related to the grain of all crops); special (used for grain of individual crops); safety indicators.

To the group general indicators of grain quality include: color, smell, taste, pest infestation of grain stocks, humidity and weediness. These indicators are determined when assessing the quality of any grain intended for a particular purpose.

The group of mandatory grain quality indicators includes such indicators that are inherent only in individual crops or grain batches used for a specific purpose. To mandatory indicators include: vitreousness, quantity and quality of raw wheat gluten, bulk density (wheat, rye, barley and oats), fine grain content, grain size, filminess and percentage of the kernel in cereal crops.

grain quality indicator flour

Safety indicators include the content of toxic elements, mycotoxins and pesticides, harmful impurities and radionuclides, which should not exceed the permissible levels according to SanPiN

To the group additional indicators quality includes indicators of the chemical composition of grain, the content of microorganisms, the activity of enzymes, etc.

The state standard stipulates that the initial unit in determining the quality of grain is the batch.

The consignment is any quantity of grain that is homogeneous in quality (according to organoleptic evaluation), intended for simultaneous reception, delivery, shipment or stored in one silo, bin, warehouse.

The quality of each batch of grain is determined based on the results laboratory analysis an average sample made up of notches taken from the lot.

excavation- a small amount of grain taken from the batch at one time to compile the initial sample.

The selection of recesses for compiling average samples is a very important and crucial step in determining the quality of the grain. The accuracy of determining the quality of a batch of grain depends on how correctly the recesses are selected and the average sample is compiled.

The totality of all recesses selected from a batch of grain constitutes the original sample. The part of the original sample allocated for laboratory testing is called the average sample. If the batch of grain is small, then the original sample (weighing up to 2 kg) is also medium.

To determine individual indicators of grain quality (bulk density, moisture content, contamination, etc.), a small part is isolated from the average sample, which is called a sample. The size (mass) of the sample depends on the type of analysis and the type of grain.

Before taking an average sample, it is necessary to establish the homogeneity of the lot on the basis of organoleptic determinations, i.e. its uniformity in appearance.

When removing the recesses and in the process of compiling the initial and average samples for analysis, it is necessary to strictly follow the instructions of the standards and all those measures that ensure the complete invariability of grain samples from external influences: drying and moistening, the acquisition of foreign odors, etc.

Determination of color, smell, taste and other indicators of grain quality

The average grain sample in the laboratory is subjected to analysis, which is carried out according to the scheme (Fig. 1).

Fig.1.

After isolating the sample, the color, smell and taste of the grain of the average sample are organoleptically determined.

Color. The most important indicator of quality, which characterizes not only the natural properties of grain, but also its freshness. Grain is considered fresh in which no changes have occurred under the influence of unfavorable conditions of ripening, harvesting and storage. Fresh grain should have a smooth surface, natural luster and color characteristic of the grain of this crop.

The test sample is compared in color with the standards of grain types and subtypes available in the laboratory, common in the given area (region, territory, republic). For ease of comparison, it is recommended to use a frame (Fig. 2).

Fig.2.

The test sample of grain is placed in the middle of the frame in a square hole closed by a latch, which is located on the rear wall of the frame.

In separate sections, located around the hole and tightly closed with a wooden board, pre-prepared samples are poured, which serve as working standards.

Grain color is best determined in diffused daylight. As a last resort (with the exception of controversial ones), it is possible to determine the color in other conditions.

As a result of moistening by atmospheric precipitation and subsequent drying during germination, self-heating, etc. shells lose their smooth surface and luster, the grain becomes dull, whitish or darkens. Such grain is considered discolored (in the presence of light shades) or darkened (in the presence of dark shades).

Oats or barley are considered dark when they lose their natural color or have dark ends due to unfavorable harvesting and storage conditions.

For grain overheated during drying, as well as heated, darkening is characteristic, reaching red-brown and black shades of color in the last stages of self-heating. Charred grains, i.e. painted black, are formed during prolonged self-heating and high temperature. Grain of wheat, captured on the vine by frost (frost), is characterized by a reticulum and can be whitish, green or very dark. Dry grain is mostly small, feeble, usually has a light, whitish tint.

Thus, a change in the natural color and luster of normal grain is the first indication that the grain has been exposed to adverse conditions of ripening, harvesting, drying or storage. The chemical composition of such grain is different from the chemical composition of normal grain.

Smell. A very important sign of quality. Healthy grain should not have any odors that are not characteristic of it.

The grain perceives the smell mainly from weeds containing essential oils, from other impurities and foreign substances with which it comes into contact.

The odors associated with a change in the state of the grain include malty and musty, which arise as a result of exposure to micro-organisms on the grain.

Grain can acquire an extraneous smell when stored in contaminated warehouses or during transportation in wagons and other vehicles without proper processing.

The ability to recognize odors develops gradually in a laboratory assistant and requires training and experience. The collection of odors, which should be in any modern laboratory that conducts organoleptic determinations, will provide the necessary assistance in this. The collection should include grain samples with odors used as references.

External conditions have a great influence on the sharpness of smell. The laboratory should have good ventilation, lighting, clean air without extraneous odors, room temperature should be constant (about 20 ° C), relative humidity of 70-85%. In a very dry room, the laboratory assistant's perception of smell is reduced.

It is necessary to pay special attention to the first sensation, as it is usually the most correct.

Depending on the presence of weeds and other impurities in the grain, one should distinguish between:

• The smell of sweet clover acquires grain from the admixture of seeds of this weed. The seeds contain coumarin, which has a strong odor that is transferred to the flour;
• Garlic smell acquires grain from the admixture of fruits of wild garlic;
• The smell of coriander acquires grain from the admixture of seeds of an essential oil crop - coriander;
• smut smell acquires grain from contamination with wet smut spores or the presence of an admixture of smut sacs in it;
• wormwood smell and bitter wormwood taste grain acquires from the infestation of wheat and rye crops different types wormwood, of which the most common, causing noticeable damage to grain, are two types: wormwood and Sievers wormwood. The presence of a wormwood smell is due to the content of essential oil in wormwood plants, and the bitter taste is caused by the presence of a bitter substance in it - absinthine. The smell and taste of wormwood are transmitted to the grain mainly during threshing, when the hairline of the leaves, baskets and stalks of wormwood is destroyed; hairs in the form of fine dust settle on the surface of the grain. Wormwood dust contains water-soluble absinthine, which easily, especially in moist grain, penetrates into the shells and, as a result, the grain acquires bitterness. It has been established that the mechanical removal of wormwood dust does not significantly reduce the bitterness in the grain. The bitterness in wormwood is removed by treating it in washing machines with warm water. Grain-receiving enterprises accept wormwood grain, but such grain must be washed before processing;
• · smells of sulphurous gas and smoke a - perceives grain in the process of drying with incomplete combustion of fuel. Typically, these odors appear when coals with a high sulfur content are used in the furnaces of dryers;
• tick smell - a specific unpleasant smell, appears as a result of the strong development of ticks;
• smell of insecticides used for fumigation.

Odors associated with changes in grain condition include:

• moldy, usually appearing in wet and damp grain as a result of the development of mold fungi, which spread especially strongly on grains with a damaged shell (broken, corroded). The moldy smell is unstable, it disappears after drying and airing the grain. The presence of such a smell does not give grounds to consider the grain defective;
• sour smell - result various kinds fermentation, especially acetic acid, which gives a sharper smell; grain with a sour smell (not eliminated by airing) refers to the first degree of defectiveness;
• malt or moldy-malt - an unpleasant specific smell that appears under the influence of processes occurring in the grain mass during self-heating, increased development of microorganisms, in particular molds, and does not disappear when aired. In grain with such a smell, partial darkening of the embryos, shells, and sometimes the endosperm is observed; the chemical composition changes: as the grain deteriorates, the content of amino compounds and ammonia increases, as well as the acidity and the amount of water-soluble substances; flour-grinding and baking properties of wheat change. The baked bread is dark in color.

It has been established that if the stored grain, in addition to self-heating, germinated, the amount of ammonia in the grain increases more intensively.

For grain in the initial stage of damage, darkening is observed primarily in the embryo as the most rich in nutrients (mainly fat) and less protected from the influence of the external environment (absence of cells of the aleurone layer).

Therefore, for an approximate assessment of the state of the grain of wheat, rye and barley, it is recommended to determine the number of grains with a darkened germ. To do this, a sample of 100 grains is isolated from a sample of grain, purified from impurities, and the tip of the embryo is cut off with a sharp razor.

The cut point is viewed under a magnifying glass with a slight increase and the number of grains with a darkened embryo is counted.

Cases have been observed where the malty aroma resulting from nested self-heating can be transferred to the rest of the normal grain mass as it comes into contact with the heated grain, although its color and other quality indicators do not change.

It is also necessary to distinguish between the malt smell that occurs as a result of the development of the initial stages of grain germination. The grain has a pleasant smell inherent in malt. Nevertheless, if a malt smell is detected, regardless of its origin, the grain is referred to the first degree of defectiveness.

A musty and moldy musty smell occurs as a result of the vital activity of microorganisms, especially mold fungi, penetrating from the surface of the shells into the depths of the grain and causing the formation of decay products of organic substances.

The musty smell is usually persistent, it is not eliminated by airing, drying and washing the grain and is transmitted to cereals, flour and bread. The taste of the grain also changes. Grain with musty and moldy musty odors should be attributed to the second degree of defectiveness;

putrid smell - the unpleasant smell of rotting grain. Occurs in grain during prolonged self-heating, as well as as a result of the intensive development of pests of grain reserves. In connection with the breakdown of proteins into amino acids, the content of ammonia increases significantly. There is a darkening of the membranes and endosperm, the latter is easily destroyed by pressure.

Grain with a putrid or putrid musty odor is classified as the third degree of defectiveness. Grain batches with a completely changed shell and brown-black or black endosperm, charred and subjected to self-heating at high temperatures, are referred to the fourth degree of defectiveness.

The smell is determined both as a whole and in the ground grain, and in the quality documents it is indicated in which grain the smell was found.

For better recognition of odors, it is recommended to warm a handful of grain with your breath or warm it in a cup under an electric light bulb, on a battery or over boiling water for 3-5 minutes. The grain can be poured into a glass, pour hot water = 60-70 ° C, cover the glass with glass and leave for 2-3 minutes, then drain the water and determine the smell of the grain.

The determination of odor by the standard method (organoleptically) is subjective and often doubtful.

To eliminate subjectivity and exclude possible error in assessing the quality of grain, VNIIZ has developed an objective method for determining the defectiveness of grain, based on the quantitative accounting of ammonia content.

The increased content of ammonia, indicating the partial destruction of protein substances, is the main objective indicator of the loss of freshness in the grain.

The method of objective determination of the degree of defectiveness is used so far only for wheat grain.

Taste. It is determined in cases where it is difficult to establish the freshness of the grain by smell. To do this, a small amount (about 2 g) of pure ground grain (without impurities) is chewed, which is isolated from the average sample in an amount of about 100 g. Rinse your mouth with water before and after each determination. There are sweet, salty, bitter and sour tastes. In sprouted grain, a sweet taste appears, with the development of mold, a sour taste is felt, and in wormwood grain - bitter. When establishing the quality of defective grain, additional definitions are recommended that give an idea of ​​the state of the grain. To do this, you need to install:

• - the number of germinated grains (according to the standard);
• - the number of grains damaged and spoiled by self-heating (according to the standard);
• - in wheat, rye and barley - the number of grains with a darkened germ;
• - resistance of the odor to be determined (leave the whole and ground grains for some time in an open cup). If, after airing the grain, the smell does not disappear, this indicates deeper changes that have occurred in it, in which the grain is considered defective and the degree of defectiveness is established;
• - the quantity and quality of gluten in wheat, as well as its smell. In the damaged grain, gluten acquires a dark color and the smell of rancid fat (linseed oil).

In controversial cases, taste and smell are determined in bread baked from ground grain by the express method described below. The smell should be determined both in hot and chilled bread cut in half.

Humidity is an important indicator of quality. It ranges from 12.0 to 15.5% (oatmeal - no more than 10%), depending on the type of cereal. With an increased moisture content, cereals are poorly stored.

Infestation with barn pests is not allowed. When determining infestation, dead pests are not taken into account, they are classified as contamination that is not allowed in cereals that do not require preparation for cooking (for example, oatmeal, semolina), as well as in rice cereals of extra and higher varieties.

The percentage of a benign kernel shows the amount of full-fledged cereals, which determines the commercial grade. The standards set its content for each type and variety of cereals. The content of a benign nucleus is calculated taking into account the content of impurities. Impurities in cereals include weed impurities (mineral, organic, harmful), unshelled, spoiled kernels, muchel (flour dust) and some other fractions, in addition, broken (split) kernels in excess of the permissible norm.

Consumer properties of cereals depend on its type and technological processing. This indicator consists of the duration of cooking, the increase in volume and mass, the state of the porridge after cooking. The duration of cooking is not the same and can vary from 3-5 minutes for quick-cooking flakes, semolina to 60-90 minutes for pearl barley and oatmeal.

vitreousness characterizes the grain structure, the relative position of tissues, in particular starch granules and protein substances, and the strength of the bond between them. This indicator is determined by transillumination on a diaphonoscope and counting the number of grains (in%) of vitreous, semi-vitreous, mealy consistency. In a vitreous grain, starch granules and protein substances are packed very tightly and have a strong bond, there are no microgaps between them. Such grain during crushing breaks into large particles and almost does not give flour. There are micro-gaps in the floury grain, which give the endosperm friability, and when translucent on a diaphonoscope, they scatter light, causing the opacity of the grain. Grain standards provide for the determination of the vitreousness of wheat and rice.

Nature- mass of the established volume of grain. It depends on the shape, size and density of the grain, the state of its surface, the degree of filling, the mass fraction of moisture and the amount of impurities. Nature is determined using a purka with a falling weight.

Grain with high values ​​of nature is characterized as well developed, containing more endosperm and less shells. With a decrease in wheat by 1 g, the flour yield decreases by 0.11% and the amount of bran increases. The relationship between the nature and the amount of endosperm has been established.

Nature different cultures has unequal value, for example, the nature of wheat - 740-790 g / l; rye - 60-710; barley - 540-610, oats - 460-510 g/l.

Fall number characterizes the state of the carbohydrate-amylase complex, makes it possible to judge the degree of grain germination. When the grain germinates, part of the starch passes into sugar, while the amylolytic activity of the grain increases and the baking properties deteriorate sharply. The lower the index, the higher the degree of grain germination. The rate of fall (s) of the stirrer rod through the water-flour mixture determines the number of fall. This indicator is normalized for wheat and is the basis for the division into classes of rye.

Gluten ( determined only in wheat) is a complex of protein substances of the grain, capable of forming a coherent elastic mass when swollen in water. High gluten wheat flour can be used alone in bread making or as an improver for weak wheats.

Filminess - the content of flower films in filmy cereals and fruit membranes in buckwheat, expressed as a percentage of mass and ril. Filminess varies greatly depending on the crop, its I orth, area and year of cultivation (for buckwheat - 18-28%, for oats - 18-46, barley - 7.5-15, rice - 16-24%). The larger the grain, the less filminess and the greater the yield of the finished product.

size determined by linear dimensions - length, width, thickness. But in practice, the fineness is judged by the results of sifting grain through sieves with holes of certain sizes and shapes. Large, well poured grain gives a greater yield of products, as it contains relatively more endosperm and fewer shells.

The grain size can be characterized by a specific indicator - the mass of 1000 grains, which is calculated on a dry matter basis. Grain is divided into large, medium and small. For example, for wheat, the weight of 1000 grains ranges from 12 to 75 g. A large grain has a mass of more than 35 g, a small one - less than 25 g.

evenness is determined simultaneously with the fineness by sieving on sieves and expressed as a percentage of the largest residue on one or two adjacent sieves. For processing, it is necessary that the grain be leveled, homogeneous.

Density grain and its parts depends on their chemical composition. A well-filled grain has a higher density than an unripe one, since starch and minerals have the highest density.

Depending on the significance, the quality indicators of wheat grain are divided into three groups:

Mandatory indicators for all batches of grain. The indicators of this group are determined at all stages of work with grain, starting from the formation of batches during harvesting, they include: signs of freshness and ripeness of grain (appearance, smell, taste), pest infestation of grain stocks, humidity and impurity content.

Mandatory indicators in the evaluation of batches of grain for a specific purpose. An example of normalized indicators of grain or seeds of some crops is the nature of wheat, rye, barley and oats. Big role play specific indicators of the quality of wheat (glassiness, quantity and quality of raw gluten).

Additional quality indicators. They are checked as needed. Sometimes they determine the complete chemical composition of the grain or the content of certain substances in it, reveal the features of the species and numerical composition of the microflora, salts of heavy metals, etc.

The main indicators of grain quality: Humidity, freshness, contamination. Grain moisture is understood as the amount of hygroscopic water content (free and bound) in it, expressed as a percentage of the grain mass, together with impurities. The definition of this display is mandatory when assessing the quality of each batch of grain.

The water content in the grain of the main cereal crops is normalized by basic conditions and ranges from 14-17% depending on the areas of production. If the water content in the grain exceeds the established norm, then at the time of purchase there are discounts on the mass (percentage per percentage) and a drying fee is charged at 0.4% of the purchase price for each percentage of moisture removed. If the grain moisture is below the basic conditions, an appropriate weight allowance is charged. The standards provide for four states in terms of humidity (in%): dry -13 - 14, medium - dry - 14.1 - 15.5; wet - 15.6 - 17 and raw - over 17. Only dry grain is suitable for long-term storage.

Example: The basic conditions for the Moscow region for wheat are 15%. The grain receiving point received two batches of wheat: one with a moisture content of 19%, and the other with 13%. For the first batch, the deviation from the basis is 4%, for the second - 2%. In the first case, the discount on the mass of grain will be 4%, and 1.6: of the purchase price will be deducted; in the second case, a surcharge on the mass of 2% will also be payable.

Grain freshness includes (taste, color, smell).

By color, gloss, smell, and sometimes taste, one can judge the quality factor or the nature of defects in a batch of products.

The condition of the batch makes it possible to judge the stability of the grain during storage and its characteristics during processing, and finally, they to some extent characterize the chemical composition of the grain, and therefore its nutritional, fodder and technological value.

The color of the grain can be affected by: frost capture at the root, dry wind capture, damage to grain by a bug-turtle, violation of thermal drying regimes.

Grain with a changed color is referred to as a grain impurity.

The smell of grain. Fresh grain has a specific smell. Foreign smell indicates a deterioration in the quality of grain: musty, malty, moldy, garlic, wormwood, putrid.

Grain taste. The taste of normal grain is weakly expressed. Most of the time it is fresh. Uncharacteristic tastes for grain are: sweet - arising during germination; bitter - due to the presence of particles of wormwood plants in the grain mass; sour - felt during the development of mold on the grain.

Grain contamination is understood as the amount of impurities found in a batch of grain for food, feed and technical purposes, expressed as a percentage of the mass, called contamination. Impurities reduce the value of the batch, so they are taken into account when calculating for grain.

Many impurities, especially of plant origin during the harvesting period and the formation of the grain mass, can contain significantly more moisture than the grain of the main crop. As a result, they contribute to an undesirable increase in the activity of physiological processes. In clogged batches of grain, the process of self-heating occurs much easier and develops faster. Grain admixture includes defective grain of the main crop: strongly underdeveloped - feeble, frosty, sprouted, broken (along and across, if left. Impurities are divided into two groups: Grain and weed.

Grain impurities include such grain components (more than half of the grain), damaged by pests (with unaffected endosperm), darkened during self-heating or drying; in wheat, this also includes grains damaged by a tortoise bug. In membranous crops, grain impurities include collapsed (freed from the flower film) grains, since they are strongly crushed during the processing of the main grain.

The grains of others cultivated plants when assessed, they can fall into both grain and weed impurities. This is guided by two criteria. First, the size of impurity grains. If the admixture sharply differs from the main crop in terms of size and shape, then it will be removed during grain cleaning, therefore such a culture is referred to as a weed impurity. For example, millet or peas in wheat. Secondly, the possibility of using the admixture for the intended purpose of the main culture. If the admixture gives a product, although somewhat worse in quality than the main crop, then it should be attributed to the fraction of grain impurities. If it sharply reduces the quality of the processed product, then it is referred to as a weed impurity.

Weed admixture is divided into several fractions, different in composition. Mineral admixture - dust, sand, pebbles, pieces of slag, etc. are highly undesirable, since they add a crunch to the flour, making it unfit for consumption; organic admixture - pieces of stems, leaves, glumes, etc.; spoiled grain of the main crop and other cultivated plants with completely eaten pests or darkened endosperm; seeds of cultivated plants that were not included in the composition of the grain admixture; seeds of weeds grown in fields with cultivated plants. , . When evaluating grain, weed seeds are divided into several groups: easily separable. difficult to separate, with an unpleasant odor and poisonous. The seeds of field cornflower, rye bonfire, wheatgrass, spreading buckwheat and bindweed, etc. are easily separated from most crops; it is difficult to separate (close in size and shape to certain cultivated plants) the seeds of wild oats from oats, wheat and rye, wild radish and Tatar buckwheat from buckwheat and wheat, gray foxtail from millet, wild millet and kurmak from rice; weeds with an unpleasant odor include wormwood, sweet clover, wild onions and garlic, coriander, etc.

Poisonous weed seeds are especially undesirable in the grain mass. This group includes cockle, which is distributed almost throughout the country. Its seeds contain - lycoside agrospermine, which has a bitter taste and narcotic effect. Gorchak (foxtail sophora) has not only poisonous and bitter seeds, the whole plant is poisonous.

Ergot most often affects rye, much less often other cereals. In the grain mass, ergot occurs in the form of sclerotia (mycelium) - black-violet horns, 5-20 mm long. The toxicity of ergot is due to the content of lysergic acid and its derivatives - ergosine, ergotamine and others, which have a strong vasoconstrictive effect. This property of ergot is used in medicine to obtain drugs that stop bleeding.

It occurs in the grain mass in the form of irregularly shaped galls, shorter and wider than the grain, no grooves, thick shell, tuberculate surface, brown color. Galla is 4-5 times lighter than wheat grain.

Inside the gall there are up to 15,000 eel larvae that can remain viable for up to 10 years. A significant admixture of galls worsens the baking quality of grain, gives the bread an unpleasant taste and smell.

Grain damaged by the turtle bug, a field pest that most often attacks winter wheat, but also feeds on other cereals. A dark dot remains at the puncture site, surrounded by a sharply defined spot of a wrinkled whitish shell, the endosperm crumbles at the bite site when pressed. The turtle bug leaves very active proteolytic enzymes in the grain. Strong wheat with a content of 3 - 4% of damaged grains goes into the weak group. The gluten from the grain damaged by the turtle bug is rapidly liquefied by these enzymes. The baked bread is of small volume and porosity, dense, with a surface covered with small cracks, tasteless.

Mycotoxicoses - defeat by various fungal diseases during cultivation, harvesting, violation of grain storage regimes. The previously mentioned ergot and smut are examples of such diseases.

Fungi of the genus Fusarium damage the grain of all crops, more often real cereals. Infection occurs in the field, but the development of fungi in storage stops only when the grain moisture content drops to 14%. Grain that has overwintered in the field often accumulates many toxins from this fungus. Mushrooms of this genus produce a number of toxins, including trichothecenes and zearalenone, which cause severe poisoning in humans and animals. In humans, the consumption of bread obtained from flour containing Fusarium mycelium causes poisoning; similar to intoxication: lightheadedness, dizziness, vomiting, drowsiness, etc. appear. At the same time, the function of the bone marrow is weakened, so the proportion of leukocytes in the blood drops sharply. Then necrotic angina develops. Grain affected by Fusarium is stored separately from food and fodder and used for technical purposes.

Mycotoxins also form other mold fungi that can develop on the surface of grain and products of its processing under unfavorable storage conditions.

Aflatoxins that affect the liver and have a pronounced carcinogenic effect are produced by fungi of the genus Aspergillus (Asp.flavus and Asp. parasiticus). Ochratoxins are produced by fungi of the genus Penicillium.

Ochratoxins also affect the liver and are cocarcinogenic. Many other molds can also produce toxins. To date, more than 100 mycotoxins have been isolated and studied; they are resistant to temperatures used in grain processing, acids or reducing agents. Therefore, the most reliable way to protect against them food products is the exclusion of grain molding.

Grain damaged by self-heating and violations of drying regimes is also considered defective.

Indicators of grain quality for a specific purpose are: the nature of wheat grain, vitreousness, gluten.

Grain in kind is understood as the mass of the established volume of grain or the mass of 1 liter of grain, expressed in grams, or the mass of 1 g/l of grain, expressed in kilograms. Nature is of great importance, since it indirectly characterizes one of the main indicators - grain completion.

Grain completion is of great technological importance and characterizes its nutritional value.

The size of nature is affected by: the shape of the grain, surface roughness, impurities in the grain mass, humidity.

When selling grain with a quantity higher than that provided for by the basic conditions, the farms receive a surcharge on the purchase price of 0.1% for every 10 g/l, in the same amount they carry out a discount for a reduced quantity compared to the basis.

The nature of the grain affects the use of storage capacity.

For example: one batch of wheat weighing 300 tons at nature 800 g/l has a grain mass volume of 300/0.80=375 m3, the second batch weighing 300 tons at nature 730 g/l has a grain mass volume of 300/0.73=411 m3 . Consequently, the volume of grain mass of low-grade wheat is 36 m3 larger and a large storage capacity will be required to store this batch.

Vitreous grain is one of key indicators grain quality. The concept of vitreousness is based on the visual perception of the appearance of grain, due to its consistency, that is, the density of packing in the endosperm of starch grains and their cementation by grain proteins. The grain consistency of durum wheat is usually vitreous, while that of soft wheat is different, depending on the variety, geographical and soil factors, agricultural practices, etc.

3. Gluten is a complex of protein substances of the grain, capable of forming an elastic mass when swollen in water.

Gluten determines the gas-holding capacity of the dough, creates its mechanical basis and determines the structure of the baked bread. The content of raw gluten in wheat grain ranges from 5 to 36%.

All of the above indicators of wheat quality are mandatory for all producers in accordance with regulatory documentation.

When working with a crop such as wheat, you should know what its classification is. One of the main issues is the definition of the grain class, since without understanding the essence of the division, it is difficult to choose a quality product designed for specific needs.

Species and types of wheat

The primary classification divides all existing wheat into selective and wild. In turn, each of them can be hard or soft. In addition, each variety has its own individual characteristics. In order to somehow streamline all the available parameters, state standards were created.

Durum wheat differs from soft wheat both in composition and in how it behaves when cooked. Let's consider both options in more detail.

Soft

Soft wheat can be identified by very thin straws that break easily. The same can be said about spikelets. The grains themselves are covered with dense films, which are very difficult to separate. They have a rounded shape with a groove and are painted either reddish or white. Flour is made from soft culture, which is later used for baking bread. In Russia, such soft varieties as "Girka", "Kostromka", "Samarka", "Belokoloska" and others have gained popularity.

There are four main types of this wheat, which are divided into subtypes that differ in shade and vitreous grains.

solid

In durum wheat, the straws are flexible and resilient, so very often they do not even break during threshing. The spikelet is also firmly attached to the trunk. The grains themselves are quickly and simply separated from the existing films. Among the durum wheat varieties, Garnovka, Kubanka, Chernokoloska and others are distinguished. As in the case of soft wheat, there are four types of durum wheat, which, in turn, are divided into subspecies.

It should be mentioned that the gluten of hard flour is of very high quality.

Classes and their characteristics

Grades of wheat are used to indicate the quality of the grain. This parameter is determined depending on the presence of impurities, debris, as well as damaged samples. The more pieces of earth, pebbles, leaves are present, the lower the quality of the crop. All over the world, a single classification of wheat is used, which has six different classes. The first three classes (1, 2 and 3) are included in group "A". This is food wheat, which is either exported or used in the domestic food industry.

Classes 4 and 5 are included in group "B". Usually these are hard varieties, which are also used for making cereals and pasta, but, unlike group “A”, they require saturation with strong varieties. The problem is that the varieties of group "B" lack their own amount of gluten and proteins. These classes are also used for non-food purposes.

Finally, class 6 stands separately. It belongs to the forage type, has the worst quality indicators and, as a rule, is not used in the food industry. Such wheat is grown only to feed birds and animals.

It is worth mentioning that regardless of class, all grains must be clean, undamaged and smell good. If the wheat smells of rot or something chemical, then it is not recommended to use such grain. In addition, the seeds should have a color, and the amount of harmful substances should not exceed the norm.

By the way, the class of cereals also determines the final cost of wheat. If the wheat belongs to the first, second and third class, then it is called strong. The flour made from it is used to bake bread or to improve the quality of weak flour. Grade 4 wheat has a gluten level in excess of 23%, so it can be used to make flour without the need for strong varieties. Grade 5 wheat is very weak, so it cannot be consumed without the addition of better varieties. Finally, the sixth grade is either processed into glucose or used for feed production.

How to determine the quality of grain?

Grain quality is determined by gluten, or rather, by its quality and quantity, smell, color and appearance. This also includes such nuances as the presence of impurities, germinated grains and vitreousness. All of the above indicators depend on important factors affecting the development of the plant, which can be divided into two groups. The first group is those factors that a person is not able to influence, for example, excessive precipitation, temperature, or the process of cultural development. The second group is those moments that a person is able to influence. This includes fertilization, preventive procedures, weeding, timely collection of grain and its proper storage.

The vitreousness of the grains will largely determine which class the wheat belongs to. For the first class, the vitreousness must reach a minimum of 70%. A low percentage of vitreousness indicates a low grain quality. In appearance, you can try to determine the level of vitreousness by looking closely at the seeds: if they look mealy and loose, and the cut line is painted white, this indicates a low rate.

The amount of gluten also determines the class of the crop. This indicator can be determined by washing the dough. When starch and other substances that can be dissolved in water are washed off, pure gluten remains. After drying and kneading this protein, you can weigh the substance and determine the mass of gluten. By calculating its ratio to the total weight of flour, we can draw conclusions about its class.

The quality of gluten can be determined by its appearance. If the substance is light, tending to a yellow or gray tint, then gluten is in order. If the color is dark, then this indicates that the substance is spoiled. It was either stored incorrectly or developed in inappropriate conditions. More accurate information is provided by the special IDK-1 device, which is capable of calculating the deformation index.

The class of wheat is also determined by the amount of protein available. If the flour belongs to group "A", then this figure should range from 11% to 17%. The minimum rate for the first class is 14%. The lower the protein content, the worse the culture. As a result, the quality of baked bread and pasta made from this grain is also worse. Its maximum value is 23%, and the minimum indicator inherent in class 5 is only 10%.

It is worth mentioning that hard varieties are rich in protein.

Parameter table

Permissible quality indicators are easy to find in a special table. Judging by it, the vitreousness of wheat should be at least 70%, and the moisture content should not exceed 14%. The amount of impurities in the grains should be about 5%, and debris - about 1%. Mineral impurities are allowed even less - only 0.3%. Speaking of spoiled grains, it is worth noting that there should be very few of them (only 0.3%).

The permissible number of infected grains is greater - as much as 5%. Harmful impurities are allowed only 0.2%. Protein in wheat should be at least 14%. A special device "IDK" should show a deformation index from forty-five to one hundred. Determining the quality of grain, you need to take into account all the numbers. In the event that at least one of the above indicators does not correspond to the norm, the grain is transferred to a lower class.

For information on how the quality of wheat grain is determined, see the video below.

Depending on the purpose of the grain, its quality indicators are divided into three groups:

1. obligatory for all batches of grain - signs of freshness and maturity (appearance, smell and taste), infection of grain with pests (insects) and seeds of legumes - grains, humidity and content of impurities;
2. mandatory when evaluating batches of grain of certain crops for a specific purpose - the nature of wheat, rye, barley, oats; for cereal crops - evenness, content of the kernel and flower films; malting barley is determined by the ability to germinate and viability; indicators of germination and germination energy are obligatory for rye, oats and millet used for malting in alcohol production; in wheat, vitreousness, quantity and quality of gluten, protein content are determined;
3. additional quality indicators determined depending on the need that has arisen at various stages of the grain turnover: the chemical composition of the grain, the species and numerical composition of the microflora (infection with helminthosporium, fusarium, etc.), the residual content of pesticides and fumigants in the grain, the content of radioactive substances.

Grain Quality Determination

Normally ripened grain, which has not been subjected to adverse effects, has its own shape, size, condition of integumentary tissues, color, etc. The state of the grain according to these features has common name freshness.

By appearance

Appearance (color and gloss)- signs that change due to unfavorable conditions during the period of formation and maturation (dry winds, early frosts, germination in the ear), pest damage, active development of phytopathogenic and saprophytic microorganisms, improper processing (drying, cleaning, disinfection).

The grain with a changed color has a chemical composition that differs from the chemical composition of normal grain, as well as a deformed structure of the shells, which affects its technological advantages. Such grain, in accordance with the standards, usually refers to draft, and sometimes to trash impurities, the content of which is normalized in the standards.

The results of studies conducted by VNIIZ showed that grain discoloration worsens its quality, and in strong wheats, for this reason, their mixing value decreases - the ability to improve weak wheats, in addition, the yield of flour, especially the highest grade, decreases, its ash content increases

By smell

Smell in grain appears as a result of adverse effects on it. Odors are divided into two groups of sorption origin (odors of essential oils acquired during the processing and storage of grain masses, in case of violation of the rules of circulation) and decomposition resulting from biological processes occurring in the grain, the formation of decay products of organic substances (typical odors of this group are barn , malty, musty and putrid). Extraneous odors in food grains are not allowed, as they are stored in the products of its processing (flour, cereals). The possibility of using grain with foreign odors for the production of animal feed is decided by the veterinary authorities.

Taste

Grain taste determine when doubts arise when identifying odors (for example, if the grain has a malty or sagebrush smell).

By infection

Batches of grain and seeds of legumes infected with pests and grains are considered substandard. Restrictive conditions allow them to be infected only with ticks. Losses in the mass and quality of grain and products of its processing are very high. They not only eat grain, but also pollute it, and in some cases make it unsuitable for its intended use. The greatest danger, both in terms of distribution area and damage caused, is represented by barn and rice weevils, small flour beetle, pretenders, grain grinder, red flour eater, barn (bread) moth, mill moth, bread mites.

Infection of grain with pests, depending on the value of the indicator of the total density of infection (number of specimens per 1 kg), is characterized by five degrees.

• I degree - up to 1 copy. per kg
• II degree - St. I up to 3 copies per kg
• III degree - St. 3 to 15 copies per kg
• IV degree - St. 15 to 90 copies per kg
• V degree - St. 90 copies per kg

Infection of seeds of legumes with caryopses is expressed as a percentage of the weight of the test sample (100 g - for peas, chines, chickpeas, lupins, wikis;

200 g - for lentils, beans, fodder beans).

Humidity

Grain moisture as an indicator of quality, it has a dual meaning: economic and technological. The basis of calculations for grain when buying (selling) it, as well as for accounting for grain in state resources, is based on basic moisture standards. For deviations of humidity from the basic conditions, discounts or allowances are applied to the physical mass in a ratio of 1: 1, in addition, a fee is charged for drying.

In order for the grain masses to be preserved for a long time with minimal losses, they must be in a dry state, i.e. when there is no free moisture in them. Grain processing also requires a certain moisture content, which is usually in the range of 14-16% for cereals and legumes, and even lower for oilseeds. If the humidity is above the established limits, then the grain must be dried before processing.

By weediness

Infestation- the amount of impurities in the grain, expressed as a percentage of its mass. The classification of impurities in commercial grain is based on the principle: the degree of influence of this type of impurities on the yield and quality of the products produced, and in fodder grain - on the feed value.

Based on this, the grain mass is divided into three parts:

• main grain
• grain admixture
• trash admixture.

Consider these three parts using the example of a grain of wheat.

• Main grain- whole and damaged grains of wheat, which, by the nature of the damage, are not related to weed or grain impurities.
• Grain admixture- grains of the main crop, deformed (sprouted, feeble, crushed, swollen during drying), immature, damaged by self-heating, corroded and broken, regardless of the nature and size of the damage, in an amount of 50% of their mass (the remaining 50% refer to the main grain), grains of other cultivated plants that are close in value to the grain of the main crop and used for their intended purpose. Since sprouted grains sharply reduce the quality of gluten in wheat, their content in this crop, depending on the class, is strictly regulated (1-5%).
• Weed impurity- organic and mineral litter, seeds of all wild plants, seeds of cultivated plants not classified as grain impurities, spoiled grains, harmful impurities. Among the mineral admixture, the hard-to-separate admixture, pebbles, is limited to one percent. When processing grain and baking flour, the pebbles must be separated, in case of impossibility of complete separation, the resulting flour will be non-standard;! on a crunch; the total amount and composition of harmful impurities is also regulated, with a total allowable amount of 1%, ergot and smut are allowed no more than 0.05%. seeds of poisonous weeds not more than 0.3%, Trichodesma gray is not allowed. Otherwise, the flour will be unsuitable for food purposes.
• Grain nature- the mass of grain in a certain volume. In Russia and in a number of other countries where the metric system of measures has been introduced, nature is characterized by the mass of a liter of grain in grams or a hectoliter in kilograms. The technique for determining the nature of grain is extremely simple and short. The method used in Russia for determining nature is similar to the methods adopted in Europe, the USA, Canada and a number of other countries.

Scientific research and the experience of flour mills have confirmed that the higher the grain, the more finished the grain (with other identical quality indicators), i.e. it contains more endosperm and fewer shells, which ultimately determines the production of more flour and less bran.

Reducing the nature of wheat against the norm according to mill conditions (775 g/l) for each gram reduces the amount of food products (flour) received by 0.05% due to an increase in fodder products - bran in the same amount. It is not advisable to use wheat with a grain size below 690 g for varietal grinding.

Abroad, the nature of grain is also given great importance and its norms in the standards are supported on high level. For example, the Canadian standard for the highest class of wheat, Western Spring White No. 1, sets the minimum norm by nature at 78.0 kg/hl and No. 2 at 76.0 kg/hl. The world-famous Swiss company "Büller", which builds mills with the most advanced technology, guarantees the production of 75% of flour of the highest grade type only if wheat with a grain content of at least 785 g / l is processed.

By evenness

Grain evenness- homogeneity of the party in its size. If the grain in the batch is basically the same in size, then it is considered leveled. Grain evenness depends on the following factors: sowing with calibrated seeds, seed germination energy, simultaneity and quality of all agronomic measures for crop care, soil homogeneity of a given field (relief and other indicators). The main of these factors is the sowing of varietal seeds. In this case, the grain of the grown crop, other things being equal, will be more even than when sown with ordinary grain. This is also facilitated by the high energy of seed germination, which ensures amicable ripening and good evenness of the grain.

With high agricultural technology and good soil and climatic conditions, the grain is also more even. But even if all agrotechnical rules are observed, the grain in the batches cannot all be of the same size. This is due to its non-simultaneous maturation in the ear, panicle, brush, since the flowers in the inflorescences bloom at different times, especially in the inflorescences of panicles of oats, millet, rice and buckwheat brushes.

Leveled grain is easier to clean of impurities, as it is easier to select sieves and adjust the airflow of grain cleaners. When cleaning poorly aligned grain, more impurities remain in it, useful grain gets into the waste. When processing leveled grain, the overall yield of products and its quality will be higher. For example, when peeling unleveled grain at groats, larger grains are crushed and fall into waste, which reduces the yield of products, while small ones remain in films, this worsens the quality of the product.

The evenness and content of small grains in barley intended for brewing, cereal, flour-grinding and alcohol production, as well as in the grain of oats, cereals and legumes, are strictly standardized.

Kernel content and filminess. In close connection with the indicators of completion, size and evenness is the ratio between the number of flower films and the rest of the grain (kernel). The total yield of cereals and its individual varieties during the processing of grain of filmy crops depends primarily on the percentage of pure kernels and films. Therefore, the standards for grain of cereal crops indicate the minimum acceptable kernel content for conditioned grain: for oats at least 63%, for buckwheat - 71%, for millet and rice - 74%.

Consistency of endosperm

endosperm consistency. Depending on the consistency of the endosperm, the technological and sometimes nutritional value of the grain of some crops changes. For example, a grain of rice with a vitreous consistency is more durable, during processing it gives a greater yield of cereals in the form of whole grains, and when this cereal is cooked, the grains are preserved in their entirety. Grain with a powdery consistency of endosperm is more fragile and brittle. The yield of high-grade cereals is reduced, in the porridge from such cereals, the grains are boiled and disintegrated. The consistency of the endosperm of grains of rye, barley and millet is also technological feature. Of particular importance is the consistency of the endosperm of the wheat grain. In appearance, vitreous grains of wheat are distinguished by a homogeneous semi-translucent texture, reminiscent of wax. Vitreousness of wheat largely determines the shade of grain color and is associated with its technological advantage. When grinding high-glass grain in a mill, more grits are obtained, which ensures a greater yield of flour of the highest and first grades.

Vitreous wheat proteins usually form good quality gluten. The color of glassy grain flour is white with a creamy tint, which is also transferred to baked bread. From the mealy endosperm, less high-grade flour is obtained, it has a white color with a bluish tint. It is rarely possible to develop flour with good baking properties from low-glass wheat. The minimum norms of total vitreousness at varietal grinding for soft wheat - 50% and durum - 80%. Discolored or darkened durum wheat cannot be made into standard pasta flour.

By Russian standard the total vitreousness of wheat is determined as the sum of vitreous and half the number of partially vitreous grains. In Europe and the USA, as well as in a number of other countries, vitreousness is characterized by the number of completely vitreous grains.

According to the ability to germinate

Germination energy and grain germination ability. Germination energy refers to the percentage of grains germinated in 3 days, and germination ability refers to the percentage of grains germinated in 5 days. These indicators are taken into account not only in the sowing material, but also in the purchase of malting barley. The standard stipulates that the germination capacity of malting barley should be 95% for the first class and 90% for the second class, and a viability of at least 95% in both classes.

High germination should be in grain intended for the alcohol industry. The yield of alcohol depends not only on the content of carbohydrates (starch and sugars) in the grain, but also on the degree of starch hydrolysis and its conversion into sugar. For this purpose, grain is germinated at distilleries and turned into malt, which contains many sugars and active amylase, which provides further enzymatic decomposition of starch. The ability of grain germination for malting must be at least: for rye and barley - 92%, for oats - 90% and for millet - 86%.

Bakery evaluation of wheat grain

The potential baking properties of grain (varietal characteristics), the conditions for its cultivation, processing and storage have a significant impact on the quality of future baked bread.

High-molecular protein substances of wheat grain have the ability, when kneading dough from flour (meal) and water, to form a coherent, elastic and elastic mass, which is called gluten.

Getting a well and evenly loosened bread crumb and its volume is primarily determined by the ability of the dough to retain carbon dioxide released by yeast during fermentation and proofing. The gas-holding capacity of the dough depends mainly on the quantity and quality of the gluten. At good quality and a sufficient amount of gluten, the dough is plastic and retains carbon dioxide well, which ensures the necessary volumetric yield of bread.

The bulk of gluten proteins are gliadin and glutenin.

At present, the composition of gluten, properties and many factors affecting its quality are well known. The content of crude gluten in wheat grain varies widely from 10 to 60%. High-gluten wheat is considered to contain more than 28% crude gluten.

The quality of gluten is characterized by its color, physical properties(elasticity and extensibility) and the ability to swell. Gluten can be light or dark in color. The first often has the best extensibility and elasticity. The dark color of gluten appears due to adverse effects on the grain during ripening, storage or processing. Depending on the elasticity and extensibility, gluten is divided into three groups:

1. Group I - gluten with good elasticity, long or medium extensibility, it can be used to obtain dough with good dimensional stability and sufficiently loosened, which makes it possible to prepare bread products with a large volumetric yield and porosity;
2. Group II - gluten with good or satisfactory elasticity, with short, medium or long extensibility, with a large amount of such gluten, the dough usually has a lower gas-holding capacity, bread is obtained with a lower volumetric yield and porosity, but in most cases benign;
3. Group III - gluten is very strong or with low elasticity, strongly stretching, sagging when stretched, tearing under weight under its own gravity, floating, and also crumbling, the bread is low-porous, poorly loosened with a low volume yield, not meeting the requirements of the standard.

Wheat gluten is created at the stage of grain production, but it can be improved somewhat during the post-harvest processing of grain. When grain is cleaned of impurities, feeble, underdeveloped grains are released from it, which increases the amount of gluten, and when raw grain is dried, weak gluten is strengthened.

Protein deficiency in wheat

In most grain-producing countries of the world, including Russia, there is a protein deficiency in wheat grain. A significant part of the wheat produced is weak in terms of baking qualities and in its pure form is unsuitable for obtaining good-quality baking flour from them. This problem is solved in Europe by adding dry gluten to the flour, and in Russia - by sorting strong wheat grains to the grain of weak wheat. The value of strong wheats lies in the fact that they have the ability, when added to weak ones, to improve weak wheats with low baking qualities, that is, they have the so-called mixing ability.

At one time, research institutions developed, and the State Committee of the Council of Ministers of the USSR on Science and Technology approved quality standards that characterize wheat by strength. These norms were included in the standard for strong wheat and became state standards. After that, the grain of strong wheat began to be purchased for state resources at increased prices, and, accordingly, when they were sold by rural producers to domestic or foreign buyers at increased prices.

Additional processes affecting the grain quality index

Numerous factors influence the quality of grain in the production process, but the most studied are weather conditions, soil cultivation and methods of their processing, predecessors, fertilizers, seeds and sowing, pests, diseases and weeds, irrigation, crop size, lodging of plants, methods and terms cleaning, cleaning and drying.

The value of grain is primarily determined by its chemical composition, since the content of certain substances and their ratio to a large extent characterizes the nutritional and technological qualities of grain. Therefore, the chemical composition of grain is taken into account at all stages of working with it: when breeding new varieties, developing agricultural techniques, storing, processing and processing.

The composition of grain and products of its processing includes inorganic and organic matter. Inorganic include water and minerals, organic - carbohydrates, nitrogenous substances, lipids, vitamins, enzymes, pigments and others. For example, nitrogenous are represented mainly by proteins. According to modern concepts, a protein molecule consists of a different number of amino acid residues. In total, 20 amino acids are known, of which 8 are essential (lysine, methionine, tryptophan, valine, threonine, leucine, isoleucine, phenylalanine), synthesized in plants, humans and animals receive them only with food from grain.

Unlimited grain production for Russian farms

Rural commodity producers in Russia can produce agricultural products and raw materials in unlimited quantities. Their sale for state needs in accordance with federal law Russian Federation dated November 17, 1994 "On the procurement and supply of agricultural products, raw materials and food for state needs" is not limited. Paragraph 5 of Article 3 of this law provides: "5. The Government of the Russian Federation and the executive authorities of the constituent entities of the Russian Federation guarantee the purchase of agricultural products, raw materials and foodstuffs under concluded agreements from commodity producers (suppliers) and enterprises processing agricultural raw materials.

Grain, sugar beets, oilseeds, fiber flax, livestock and poultry, milk, wool offered by the commodity producer for sale are purchased in full.

Grain quality control is regulated by the state

Agricultural products, raw materials and foodstuffs supplied for state needs must comply with state standards in terms of quality, specifications, biomedical and sanitary standards, special conditions established by agreements".

At the same time, the sale of grain and oilseeds within the country and abroad is not limited. When concluding contracts for the sale of grain and oilseeds abroad, the parties may provide for any conditions, however, in this case, it is advisable to include the following data in the contracts: the date and number of the contract (agreement), the type and quality of products in accordance with the standards in force in Russia, the quantity of products in current units of weight measurement, the price per unit weight of products or the method of its formation, who determines the quantity and quality of products, the conditions for transporting products, the terms of payments (calculations), the term of shipment, the procedure for presenting and considering claims, arbitration.

Control over compliance with state standards of Russia for grain, products of its processing and seeds of oilseeds in the course of trade-purchase operations, storage and processing is assigned to the bodies of the State Standard of the Russian Federation.