Studying wheat varieties by indicators of grain quality. Quality control and condition of grain (seeds) during storage. Inventory list of grain flow warehouse

Plants widely cultivated by humans.

Table 2.1. Average chemical composition of grain,%

	Carbohydrates	Cellulose
Wheat soft
Durum wheat

Triticale

Corn







Sunflower

The chemical composition of grain can vary significantly depending on the type of plant, agricultural technology, storage conditions and other factors.

Factors shaping quality

Grain quality is determined by a combination of internal factors - natural characteristics of plants and external factors - soil composition, climatic conditions and a combination of agrotechnical measures.

Modern breeding and genetics provide ample opportunities for creating high-yielding varieties (2-3 times higher than that of the known ones). For example, winter wheat varieties Aurora and Kavkaz, with proper care, yield up to 70-80 c / ha with an average wheat yield in the world of 22.5 c / ra. To date, breeders from different countries have developed high-coliseine varieties, rice, and barley. Work is underway to develop productive varieties of high-protein and high-gluten wheat; high-oil varieties of corn are created, from which a large amount of edible oil can be obtained simultaneously with cereals; there are positive results in the breeding of high-vitamin varieties of wheat.

Environmental factors

The presence in the soil of the required amount of moisture, nutrients, as well as favorable climatic conditions are the conditions for harvesting a high grain yield. A number of grain crops - winter rye, spring barley, winter and spring wheat - are characterized by resistance to unfavorable climatic conditions.

Soil composition and the use of mineral fertilizers act as significant factors affecting grain quality. However, the use of mineral fertilizers requires strict control of the chemical service of the agro-industrial complex. Plants should receive the necessary nutrients, taking into account their presence in the soil and the projected yield. An excess of fertilizers, as well as their lack, reduces the yield, impairs the technological and nutritional advantages of grain and can lead to the formation of harmful substances, for example, nitrosamines.

Protecting plants from harmful factors during cultivation allows you to increase the yield by 10-30% or more. Pesticides (pesticides) used in this process, such as herbicides (weed control), desiccants (to dry out plants), insecticides (pest control), fungicides (protection against diseases), retardants (growth regulation), if used incorrectly, can have an adverse effect for its quality. The accumulation of some pesticides in grain can cause them to get into processed products, therefore their amount should not exceed 0.01-5.0 mg per 1 kg of product.

Quality control grain is carried out using the following indicators: General quality indicators - mandatory signs of freshness (appearance, color, smell, taste), determined in any batch of grain of all crops, pest infestation of grain, moisture and contamination; About special, or target, - quality indicators characterizing the commodity-technological (consumer) properties of grain. They are determined in a batch of grain of individual crops used for specific purposes. This group of indicators includes hulliness and yield of pure grain (cereals), vitreousness (wheat, rice), quantity and quality of raw gluten (wheat), natural weight (wheat, rye, barley, oats), viability (malting barley). In wheat, the content of small, frost-hardening grains and grains damaged by a turtle bug is also determined; o additional, determined when necessary, - indicators of the chemical composition of grain, the residual amount of fumigants (after treatment against pests), the residual amount of pesticides, the content of microorganisms, radiation contamination, etc.

General indicators of grain quality are determined by organoleptic and physicochemical methods, and special and additional ones - by physicochemical methods.

Organoleptic methods set the color and appearance, smell and taste of the grain. Color and appearance are determined by inspection of the sample; these signs are used to recognize the belonging of a grain to a particular species (culture), type, sometimes subtype and variety, and partly to identify its state.

Physicochemical(laboratory) methods establish moisture content, contamination, natural weight, protein content and quality of gluten, pest infestation and other indicators.

Consumer value is determined by the following indicators: weight of 1000 grains, evenness, relative density or specific volume of grains, hulliness, gum-like, fiber content, protein and some others. A batch of grain, consisting of grains of good properties, can be moistened or clogged, but the main properties of the grain - its completeness, the amount of endosperm, and the chemical composition do not change significantly. Once cleaned and dried, this grain can turn out to be first class. At the same time, the grain is puny, small, with a chemical composition changed due to unfavorable biochemical and biological processes, remains poor, even if it is dried, cleaned, has a mass close to the natural standard and meets other quality requirements.

Standardization underlies the state system of grain quality management. Grain became one of the first objects of standardization, since the creation of homogeneous batches of grain, ensuring its safety required strict quality regulation. Grain quality is an important and mandatory object of state planning and control.

Rational use of grain resources of wheat, rye, barley, oats and other crops involves the use of scientifically based standards that take into account the technological advantages of grain, its varietal and other features. Standards are a means of improving the quality and safety of grain resources, drastically reducing losses at all stages of production, storage and processing of grain.

Standardization provides:

stability of the quality of grain consignments;
the presence of certain quality groups that allow for the targeted use of grain in processing industries;
better preservation of grain due to the storage of batches of the same quality;
price gradation in accordance with the most important quality indicators, as well as other tasks.

Grain standards stipulate requirements for the quality of grain, the classification of each crop, requirements for the methods of conducting technological processes, as well as for the methods used to determine the quality of grain.

Conditions and terms of transportation and storage

Premises and containers intended for storing grain and other products are carefully freed from product residues and dust, if possible, wet cleaning, disinfection and whitewashing are carried out. Be sure to free the space around the store from weeds, organic debris and other debris. They take exterminatory measures to destroy pests. It is also important to maintain the technical serviceability of grain storage facilities and equipment.

TO the most important factors affecting the condition and safety of grain, include: the moisture content of the grain mass and its environment, the temperature of the grain mass and its environment, air access to the grain mass. These factors form the basis of storage modes. Three modes of storage of grain masses are used - in a dry state; chilled; without air access.

In addition, auxiliary methods aimed at increasing the stability of grain masses during storage must be used: cleaning from impurities before storage, active ventilation, chemical preservation, pest control of grain stocks, compliance with a set of operational measures, etc.

Grain storage must be carried out at a moisture content of 14-15%. The grain must be well cleaned and free from contamination. The relative humidity in the storage should be no more than 65-70%. The favorable temperature for storing grain is from 5 to 15 ° C. Important conditions for the preservation of grain are: ventilation and maintaining cleanliness in storage facilities.

If these conditions are met, the grain of various crops retains its sowing quality for 5-15 years, technological - for 10-12 years. However, in storage practice, grain batches are renewed every 3-5 years.

They are stored in bulk and in containers in warehouses with a capacity of 500 to 5000 tons. Warehouses are built from precast reinforced concrete, brick, wood, metal, etc. In addition, elevators of powerful industrial enterprises are used for storage for receiving, processing, storing and dispensing grain. This is essentially a factory for bringing grain to the standard of consumption, where large, uniform in quality grain consignments are formed.

When storing in a grain mass, the temperature, humidity, contamination, infection by representatives of the animal world, called grain pests, as well as the color and smell of grain are checked. The timing of the check depends on the condition of the grain and storage conditions.

Loss of grain, causes of their occurrence and ways of reduction.

As a result of the active vital activity of the microflora of grain, mainly bacteria and molds, the annual losses in the world during storage are 1-2% of its dry matter. Losses in mass are accompanied by huge losses in quality. The greatest impact of microorganisms is observed in areas with high humidity, when the harvested crop provides a favorable environment for the development of microflora.

Losses in mass and deterioration in the quality of grain and grain products during storage are possible as a result of exposure to pests of grain stocks.

The pests of grain stocks that develop in the conditions of bakery enterprises, flour and cereal factories cause great damage: they destroy part of these stocks, reduce their quality, polluting them. In addition, some of them (mites and insects) are a source of heat and moisture in the grain mass (as a result of respiration), while others (rodents) spoil individual parts of production facilities, containers, etc., contribute to the spread of various infectious diseases.

Considering the great harm caused by insects and other pests to grain and grain products, it is necessary to take measures to prevent their development or to destroy them. This is, first of all, careful control over the presence of pests during the acceptance and storage of grain, as well as the state of infestation of all objects of the enterprise, ensuring a strict sanitary regime at all objects of the enterprise, creating conditions that exclude the development of insects and ticks.

The purpose of the lesson:

- study the rules for accepting grain and the procedure for sampling to determine the quality;

- familiarize yourself with the methodology for determining the amount (mass fraction) and quality of gluten in wheat grain;

- to study the requirements of the state standard of Ukraine for the quality of wheat grain;

- determine the commercial class of wheat in accordance with the requirements of the standard.

1. Rules for acceptance of grain

The grain and seeds of each crop are accepted (bought and sold) in batches. Under Party understand any quantity of grain, uniform in quality, intended for simultaneous shipment, acceptance or storage, drawn up in one quality document.

The quality document (certificate) for a batch of grain or seeds indicates:

- the date of registration of the document and the name of the sender;

- number of a car or other vehicle;

- the mass of the lot or the number of places (for example, bags);

- destination and name of the recipient;

- name and origin of the crop, harvest year;

- grade, type, subtype and class of grain;

- the results of analyzes according to quality indicators provided by the standard for the relevant culture;

- invoice number and signature of the person responsible for issuing the quality document.

If farms do not have their own laboratory, instead of a quality document, an accompanying document (consignment note) is issued, in which there is no data on the results

definitions of quality.

Consignments of grain of especially valuable varieties of wheat and other crops, malting barley are accompanied by varietal certificates.

The quality of a batch of grain is established according to the results of commodity analysis. Average sample, the mass of which for grain of cereals (wheat, barley, oats, rye) is 2 + 0.1 kg. According to its composition and quality of grain, the average sample must correspond to the composition and quality of grain of the entire batch, since it determines the commodity class of this batch.

To form an average sample of a batch of grain, first take Spot samples- small quantities of grain, selected from a batch at one time from one place. They are taken by hand with scoops, dipsticks or mechanical samplers. The number of incremental samples is determined by the lot size.

The totality of all point samples is Combined sample, which is placed in a clean, strong container not infested with pests of grain stocks. This is provided so that the quality of the selected grain does not change.

The average grain sample is isolated from the combined sample on a special divider or manually (using the envelope method). If the batch of grain is small, and the combined sample by weight does not exceed 2 kg, then it is at the same time an average sample.

To determine individual indicators of grain quality, an average sample is isolated Hinge(a small part of the average sample). The sample size depends on the nature of the analysis and the type of grain. For example, to determine the contamination of grain (the content of impurities), a sample weighing 50 g is isolated from the average sample of a batch of wheat grain.

2. Method for determining the quantity and quality of gluten

The amount (mass fraction) and quality of raw gluten in bread wheat is the most significant indicator that determines the baking properties of wheat.

The gluten content in wheat grain is determined by washing it out of dough mixed on a 25 g sample of grain, ground to a certain size, with the addition of 14 ml of water. After kneading, the dough undergoes maturation (languishing) for 20 minutes to swell the proteins of the gluten complex, after which the gluten is washed out of it in water at a temperature of 18 + 2 ° C. The grain shells, water-soluble substances and starch are completely removed from the dough, only gluten proteins (glutenin and gliadin) remain, which form a strong elastic jelly (gel). Washed gluten is called raw, as it contains up to 70% water. After partial drying in hands (before sticking) and removing excess water, the gluten is weighed on a laboratory balance with an accuracy of 0.1 g, and its content is recalculated in% of the sample weight.

The quality of gluten, in particular its elasticity, is determined on the IDK-1 device (gluten deformation index). To do this, a dense piece of washed gluten weighing 4 g is kept in water at a set temperature for 15 minutes, and then it is compressed with a punch of the device. The measurement results are noted in conventional IDK units, based on the readings of the device, the gluten quality group is determined (Table 1).

Table 1

Wheat grain gluten quality according to the IDK-1 scale

High quality gluten is light gray or light yellow in color. Dark tones in color appear due to unfavorable effects on grain during maturation, processing (overheating during drying) or storage.

3. Requirements of the state standard

to the quality of soft wheat

Requirements for the quality of soft wheat grain, which is used for baking purposes, are regulated by the new national standard of Ukraine DSTU 3768: 2009 “Wheat. Technical conditions ”, entered into force on July 1, 2009. This standard applies to wheat grain intended for use for food and non-food needs, as well as for trade, including for export.

Depending on the quality indicators, soft wheat is divided into 6 classes (classes 1-3 of group A, classes 4-5 of group B and 6 class). Wheat of group A is used for food needs (mainly in flour and bakery industries) and for export. Wheat of group B and class 6 is used for food and non-food needs and for export. The quality requirements for each class of wheat are shown in Table 2.

table 2

Grain quality indicators for soft wheat (DSTU 3768: 2009)

Indicators	Characteristics and norms for soft wheat by groups and classes
A	B	6
1	2	3	4	5
Nature, g / l, not less	760	740	730	710	710	Not limited
Vitreousness,%, not less	50	40	30	Not limited
Humidity, %, no more	14,0	14,0	14,0	14,0	14,0	14,0
Grain admixture, %, no more	5,0	8,0	8,0	10,0	12,0	15,0
In that visle						Within the grains. approx.
cereal grain	4,0	4,0	4,0	4,0	4,0
sprouted grains	2,0	3,0	4,0	4,0	4,0
Weed admixture, %, no more	1,0	2,0	2,0	2,0	2,0	5,0
Including
mineral admixture	0,3	0,5	0,5	0,5	0,5	1,0
spoiled grains	0,3	0,3	0,5	0,3	0,5	1,0
harmful impurity	0,2	0,2	0,2	0,2	0,2	0,5
Smut grain, %, no more	5,0	5,0	8,0	5,0	8,0	10,0
Mass fraction of protein, %, not less	14,0	12,5	11,0	12,5	11,0	Not limited
Mass fraction of crude gluten,%, not less	28,0	23,0	18,0	Not limited
Gluten quality: IDK device units	І-ІІ	І-ІІ	І-ІІ	Not limited

Wheat grain of all classes must be in a healthy state, without self-heating and heat damage during drying; have a smell characteristic of healthy grain (without musty, malty, moldy, putrid, wormwood, smut, smell of oil products and pesticides and other extraneous odors); have a normal color; infestation by pests of grain stocks is not allowed.

Wheat, which has lost its color as a result of unfavorable conditions of ripening, harvesting and storage, is identified as "discolored" and the degree of discoloration is determined. For wheat of groups A and B, the first and second degrees of discoloration are allowed, for wheat of class 6 - any degree of discoloration.

In case of non-compliance with the restrictive quality standard for soft wheat, at least for one of the indicators, it is transferred to a correspondingly lower class. If the indicators of the quantity and quality of gluten do not meet the minimum requirements of group A, the wheat is transferred to group B, provided that the requirements for other quality indicators are met. If at least one indicator of the quality of soft wheat does not correspond to the requirements of groups A and B, it is transferred to grade 6.

By agreement of the procurement organization, supplier and other business entities, grain moisture and impurity content are allowed above the restrictive norms, provided that such grain is brought to the quality indicators specified in the standard.

The residual amount of pesticides, the content of mycotoxins, radionuclides and harmful substances in wheat grain should not exceed the maximum permissible levels established by sanitary and hygienic rules and regulations.

4. Determination of the commercial class of soft wheat

Using the standard for soft wheat, it is necessary to determine the class of grain of different lots with different quality indicators of the 2nd group. It should be remembered that the class of grain is set according to the worst indicator. This means that if almost all indicators correspond to the norms of the 1st or 2nd class, and only one indicator corresponds to the norms of the 4th class, then wheat should be attributed to the 4th class of group B. Averaging of different quality indicators is unacceptable.

The results of determining the class of wheat are given in Table 3.

Table 3

Determination of the grain class of soft wheat

Level of quality	Grain batch number
1	2	3	4	5	6	7
Nature, g / l	770	755	760	715	775	705	747
Glassiness,%	68	85	56	60	48	35	35
Protein mass fraction,%	11,5	13,2	14,2	12,0	14,0	10,5	11,2
Mass fraction of gluten,%	22,3	25,8	28,1	23,5	28,0	18,2	19,5
Gluten quality, units IDK	65	40	70	60	80	95	105
Wheat Grain Grade

Mark for each batch the indicators that limit (limit) the quality and commercial class of grain.

Wheat grain classification

The sown area of wheat in our country is about 40 million hectares, gross harvests - 40-50 million tons, marketable grain - about 20 million tons with a downward trend. Of the 20 species of wheat known in our time, the largest area and the maximum commercial grain production in our country belongs, as in other countries, to soft and durum wheat. Soft wheat is used mainly for the production of flour, directed to the bakery, confectionery, and partly to the pasta and cereal industry. Durum wheat is the best raw material for pasta production. However, the main factor influencing the grain quality of soft and durum wheat is the variety. All soft wheat varieties are divided into strong, medium strength (valuable) and weak.

Strong wheat is a grain that is capable of producing flour that provides high quality bread. Strong wheat flour absorbs a relatively large amount of water during kneading; and the dough obtained from such flour has the ability to retain carbon dioxide well during kneading, fermentation and proofing, steadily retains its physical properties and, first of all, elasticity and elasticity. ,.

The basis for the classification of wheat grain is the type, which takes into account species characteristics (soft, hard), botanical features (spring, winter) and color intensity (dark red, red, light red, yellow-red, yellow). ,.

I. Soft spring, red-grain - dark red, red, light red. The presence of yellow, yellow-sided, discolored and darkened grains in an amount that does not violate the main background is allowed.

II. Solid spring - dark amber, light amber. The presence of whitened, discolored, powdery grains in an amount that does not violate the main background is allowed.

III. Soft spring white-grain

IV. Soft winter white-grain

V. Soft winter white grain

Vi. Solid winter

Vii. Not classified - wheat that does not meet any of the above criteria (mixture of types). The technical conditions of the standard for harvested wheat provide for dividing it into two groups: the first with quality indicators corresponding to the basic conditions, the second with deviations from the basic conditions in the direction of deterioration of moisture, nature , increasing the content of weed and grain impurities. ,.

Basic conditions are the quality standards to which a fixed price is attached when purchasing grain.

Restrictive conditions are quality indicators that establish the maximum permissible requirements for the harvested grain.

Wheat is the staple and most important food crop in most of the world. It is cultivated in more than 80 countries. The culture of wheat has been known for about 10 thousand years, in European countries it has been cultivated for over 5 thousand years, in our country for about 5 thousand years. Of the many types of wheat in world agriculture, it is mainly soft and durum wheat that is cultivated.

Bread made from strong wheat has a high volume and good dimensional stability with any dough method. A distinctive feature of strong wheat is its ability to serve as an effective improver for wheat grain with low baking properties during sub-grading. In connection with the above, it is irrational to use strong wheat directly in baking - it should only be used for sub-sorting to grain with low baking properties. The percentage of sub-grading of strong to weak wheat is determined by the level of the main indicators of technological properties of weak wheat, as well as the gluten content and its quality in strong wheat. The use of strong wheat primarily as an improver is accepted not only in our country, but also in most of the leading countries of commercial production of this crop (Canada, USA).

Wheat of medium strength (valuable) is capable of producing bread of good quality without the addition of grain of strong wheat, which meets the requirements of the standard, but it cannot serve as an improver for weak wheat.

Wheat is considered weak, which is unsuitable for baking in its pure form without adding strong. Flour from such wheat, when kneading the dough, absorbs little water, and the dough in the process of kneading and fermentation quickly loses its elastic and elastic properties. Bread, as a rule, has a small volume, reduced dimensional stability, unsatisfactory appearance and crumb condition that does not meet the requirements of the standard.

A direct method for assessing baking properties is a test laboratory baking of bread with an assessment of its quality in terms of volumetric yield, dimensional stability, appearance, crumb condition, porosity and other indicators. However, these analyzes are lengthy and complex. Therefore, when trading with grain, simpler signs are used that predetermine the consumer merits of grain.

A sign that predetermines the baking properties of grain and is determined rather quickly with high accuracy is the quantity and quality of gluten. These indicators are included in the standard for grain and flour and form the basis for the classification of wheat by baking properties and, first of all, characterize the strength of wheat and its properties as an improver. The higher the gluten content with excellent quality (first group), the higher the mixing value of wheat. The amount of gluten in a grain of wheat can vary over a very wide range: in food grains from 18 to 40% or more.,. The highest priority is given to gluten quality rather than protein content. This is explained by the fact that the baking properties of wheat, in addition to the amount of gluten proteins, are also influenced by their quality. The quality of gluten in a number of cases is of decisive importance for the quality of bread, since its variation in commercial grain is not less, but even more, and especially, in recent years, under unfavorable conditions of ripening, harvesting, or the effects of the ecological environment.

Gluten (soft wheat): top class - 36.00%; 1st class - 32.00%; 2nd class - 28.00%; 3rd class - 23.00%; 4th grade - below 23.00 to 18.00%.

Gluten (durum wheat): 1st class - 28.00%; 2nd class - 25.00%; 3rd class - 22.00%.

The quality of gluten is also influenced by the conditions for growing wheat, the degree of maturity of the grain, damage by frost, turtle bugs, etc., so it can vary widely: from 0 to 150 units. IDK and is subdivided into 5 groups. The quality of wheat grain depends not only on the quantity and quality of gluten proteins, but also on the state of the carbohydrate-amylase complex of the grain, which can be identified by the falling number indicator. This indicator has a high technological significance in those zones of commercial grain production, where its germination often takes place. When the grain germinates, starch decomposes and partially transforms into sugars with the release of moisture. At the same time, the amylolytic activity of grain increases, its properties are greatly deteriorated, which brings special troubles to bakers. The quality of the bread baked during the processing of such grain is often non-standard: the crust is flabby, the crumb color is gray, damp to the touch, jamming, has a malt smell. Falling number index in wheat grain can vary from 60 to 600 s and more. The bread turns out to be standard with a falling number of at least 150 s.

Wheat grain is classified: by moisture content: dry - 14.0%; medium dryness - 14.1-15.5%; wet - 15.6-17.0%; raw - 17.0%; By contamination: clean - up to 1.0%; medium purity - from 1.1 to 3.0%; weed - over 3.0%. Characteristics of wheat grain The quality of grain and products of its processing is regulated by standards. In GOST 13586.2 - 81 classifications are established for grain harvested for all crops - division into types, subtypes according to various criteria: color, size, shape, etc., as well as basic (calculated) and restrictive norms.

The basic quality standards are those standards that the grain must meet in order to receive the full purchase price for it. These include moisture (14-15%), grain and weed soil (1-3%), nature - depending on the culture 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 premium. For moisture and dirtiness of grain that are excessive against the basic quality standards, corresponding discounts are made on the price and weight of grain.

Restrictive quality standards are the maximum permissible lower than the basic requirements for grain, in accordance with 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 characteristics, the content of impurities and special quality indicators. Separate requirements, more stringent, are established 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 certain crops); safety indicators.

The general quality indicators include the mandatory ones, determined in any batch of grain of all crops: signs of freshness (appearance, color, smell, taste), pest infestation, moisture and weediness.

To special, or targeted , includes quality indicators characterizing the commodity-technological (consumer) properties of grain. This group includes vitreousness (wheat, rice), nature (wheat, rye, barley, oats), falling number (wheat, rye), quantity and quality of raw gluten (wheat), filminess and yield of a clean kernel (cereals), viability (malting barley). In wheat, the content of small, frost-hardening grains and grains damaged by a turtle bug is also determined.

Vitreous b characterizes the grain structure, the interposition 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 diaphanoscope and counting the number of grains (in%) of a glassy, semi-glassy, powdery consistency. In a vitreous grain, starch granules and protein substances are packed very tightly and have a strong bond; there are no micro-gaps between them. During crushing, such grain breaks into large particles and gives almost no flour. In the mealy grains there are micro-gaps, which give the endosperm friability, and when translucent on a diaphanoscope, they scatter light, causing the grain to be opaque. The grain standards provide for the determination of the vitreousness of wheat. Nature is the mass of the specified grain volume. It depends on the grain size and density, the state of its surface, the degree of filling, the mass fraction of moisture and the amount of impurities. The nature is determined using a drop with a falling weight. Grains with high nature values are characterized as well developed, containing more endosperm and fewer shells. With a decrease by 1 g of the nature of wheat, the yield of flour decreases by 0.11% and the amount of bran increases. The relationship between the nature and the amount of endosperm has been established. The nature of different crops is of different importance, for example, the nature of wheat - 740–790 g / l; rye - 60-710; barley - 540-610; oats - 460-510 g / l.,.

The number of falls characterizes the state of the carbohydrate-amylase complex and allows one to judge the degree of grain germination. During grain germination, part of the starch turns into sugar, while the amylolytic activity of the grain increases and the baking properties sharply deteriorate. The lower the indicator, the higher the degree of germination of the grain. The rate of falling from the stirrer rod through the water-flour mixture determines the falling number. This indicator is normalized for wheat and forms the basis for the division into rye classes.

Gluten (determined only in wheat) is a complex of protein substances of grain, capable of forming a coherent elastic mass when swollen in water. Wheat flour with a high gluten content can be used in baking alone or as an improver for weak wheat varieties.

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.

Coarseness is determined by linear dimensions - length, width, thickness. But in practice, the size is judged by the results of sifting the grain through sieves with holes of a certain size and shape. Coarse, well-poured grain gives a higher yield of products, since 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. The grain is divided into large, medium and small. For example, for wheat, the mass of 1000 grains ranges from 12 to 75 g. Large grain has a mass of more than 35 g, small - less than 25 g,.

Evenness determined simultaneously with the size of 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 is leveled and homogeneous.

The density of the grain and its parts depends on their chemical composition. Well-poured grain has a higher density than unripe grain, since starch and minerals have the highest density.

Features of the chemical composition of wheat grain In addition to technologically significant indicators that ensure the production of lush standard wheat bread, an important characteristic of commercial wheat grain is its nutritional value. The most important substance in wheat grain is protein. Its content in wheat grain is on average: in soft winter wheat - 11.6; in soft spring - 12.7; in solid - 12.5 with fluctuations from 8.0 to 22.0%.

With a low total protein content (below 11%), an insufficient amount of gluten protein is formed in wheat. The most important thing in wheat grain is gluten protein, which determines the technological properties of grain and flour produced from it. Only with a high amount of raw gluten (25% and more), and its good quality, you can get fluffy, tasty and healthy bread. The unique ability of gluten proteins to form a complex called gluten has predetermined the leading role of wheat among all cereals.

Gluten is a water-insoluble elastic gel formed by mixing ground wheat or flour with water, the protein content of which is 98%, a small amount of carbohydrates, lipids and minerals. Raw gluten contains 64-66% water.,.

The bulk of wheat grain is carbohydrates. They play a large energetic role in human nutrition. In wheat grain, carbohydrates are mainly represented by starch, which makes up an average of 54% in wheat grain, with fluctuations from 48 to 63%. All starch is concentrated in the endosperm. Of carbohydrates, in addition to starch, wheat grain contains sugar. A normal high-grade wheat grain has a sugar content of 2 to 7%. Sugar is mainly present in the embryo as well as in the peripheral parts of the endosperm. It is used by the grain during the first period of germination.

Without the presence of sugars in the grain of wheat and its processed products, in particular, in flour, it would be impossible to develop yeast and lactic acid bacteria in dough.

There are other carbohydrates in wheat grain as well. For example, fiber. Its content in wheat grain averages 2.4% with fluctuations from 2.08 to 3.0%.

Fiber is a part of flower films and cell walls of the membranes. Having great mechanical strength, fiber does not dissolve in water and is not assimilated by the body. Therefore, when processing wheat grain into flour, the main task of technologists is to remove the shells.,.

At the same time, the fiber of wheat grain plays a significant role in digestion: it regulates the motor function of the intestine, thereby helping to reduce cardiovascular diseases, preventing human obesity. In this regard, the bran obtained by grinding wheat grains is used as a remedy.

Fats and lipids make up 2.1% in wheat grain on average, with fluctuations from 0.6 to 3.04%. Fats in the grain of soft and durum wheat are concentrated mainly in the germ and aleurone layer and negatively affect the safety of the grain, since they are unstable during storage. Under the influence of enzymes, they are decomposed by water with the formation of free fatty acids, which are oxidized to peroxides and hydroperoxides. As a result, fat can become rancid, so the embryo is removed during flour production. Main indicators of wheat grain quality Depending on the significance, indicators of the quality of wheat grain are divided into three groups:

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

- Mandatory indicators when assessing grain consignments for a specific purpose. An example of the normalized indicators of grain or seeds of some crops is the nature of wheat, rye, barley and oats. Specific indicators of wheat quality (glassiness, quantity and quality of raw gluten) play an important role.

- Additional quality indicators. They are checked depending on the need arisen. Sometimes the full chemical composition of the grain or the content of certain substances in it is determined, the peculiarities of the species and numerical composition of microflora, salts of heavy metals, etc. are revealed.

The main indicators of grain quality: Moisture, freshness, weediness. Grain moisture is understood as the amount of hygroscopic water (free and bound) in it, expressed in% to the grain weight together with impurities. Determination 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 the basic conditions and ranges from 14-17%, depending on the production areas. If the water content in the grain exceeds the established norm, then upon purchase there are discounts on the mass (percentage for a percentage) and a drying fee is charged at 0.4% of the purchase price for each percentage of moisture removed. If the moisture content of the grain is below the baseline conditions, a corresponding weight increase is charged. The standards provide for four states of humidity (in%): dry -13 - 14, medium - dry - 14.1 - 15.5; wet - 15.6 - 17 and wet - over 17. Only dry grain is suitable for long-term storage.

Example: The basic conditions for the Moscow region for wheat are equal to 15%. The bread-receiving station accepted two consignments of wheat: one with a moisture content of 19%, and the other - 13%. For the first batch, the deviation from the baseline is 4%, for the second - 2%. In the first case, the discount on the mass of grain will be 4%, and 1.6: the purchase price will be withheld, in the second case, a surcharge to the mass of 2% will be payable.

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

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

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

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

The taste of the grain. Normal grain taste is poorly expressed. Most often it is bland. Uncharacteristic flavors for grain are: sweet - arising during germination; bitter - due to the presence of wormwood plant particles in the grain mass; sour - felt when mold develops on the grain.

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

Many impurities, especially of vegetable origin, during the harvest and grain formation period, 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 grain lots, the self-heating process develops much easier and develops faster. Grain admixture includes defective grain of the main crop: severely underdeveloped - feeble, frost-hardening, sprouted, broken (up and down, if left over, Impurities are divided into two groups: Grain and weed.

Grain impurities include such components of the grain (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 bug-turtle. In membranous crops, grain impurities include collapsed (freed from the flower film) grains, since they are heavily crushed during the processing of the main grain.

Grains of other cultivated plants, when evaluated, can fall into both grain impurities and weeds. They are guided by two criteria. First, the grain size of the impurity. If an admixture differs sharply from the main crop in size and shape, then it will be removed during grain cleaning, therefore such a crop is referred to as a trash admixture. For example, millet or peas in wheat. Secondly, the possibility of using the admixture for the intended purpose of the main culture. If the impurity gives a product, although it is 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 classified as a trash admixture.

The foreign material is subdivided into several fractions, different in composition. Mineral impurities - dust, sand, pebbles, pieces of slag, etc. are extremely undesirable, as they give a crunch to flour, making it unsuitable for consumption; organic impurity - pieces of stems, leaves, spike scales, etc.; spoiled grain of the main crop and other cultivated plants with completely eaten away pests or darkened endosperm; seeds of cultivated plants not included in the composition of grain impurities; 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. Seeds of cornflower, rye fire, 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) wild oat seeds from oats, wheat and rye, wild radish and Tatar buckwheat from buckwheat and wheat, gray bristles 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 the cockle, distributed almost throughout the country. Its seeds contain - lycoside agrospermin, which has a bitter taste and narcotic effect. Gorchak (fox-tailed 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) - horns of black-purple color, 5 - 20 mm long. Ergot toxicity is due to the content of lysergic acid and its derivatives - ergosine, ergotamine and others, which have a strong vasoconstrictor effect. This property of ergot is used in medicine to obtain drugs that stop bleeding.

In the grain mass it occurs in the form of galls having an irregular shape, shorter and wider than the grain, there is no groove, the shell is thick, the surface is lumpy, the color is brown. Galla is 4 - 5 times lighter than a grain of wheat.

Inside the gall, there are up to 15 thousand eel larvae, which are able to survive for up to 10 years. A significant admixture of gall impairs the baking qualities of the grain, gives the bread an unpleasant taste and smell.

Grain damaged by a turtle bug, a field pest that most often attacks winter wheat, but also feeds on other grains. A dark point remains at the puncture site, surrounded by a sharply delineated spot of a wrinkled whitish shell, the endosperm at the site of the bite crumbles 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. Gluten from grain damaged by a bug-turtle, under the action of these enzymes, rapidly liquefies. Baked bread is obtained with small volume and porosity, dense, with a surface covered with small cracks, tasteless.

Mycotoxicosis is the defeat of various fungal diseases during cultivation, harvesting, violation of grain storage regimes. The previously mentioned ergot and smut are examples of such diseases.

Fusarium fungi damage the grain of all crops, more often real cereals. Infection occurs in the field, but the development of fungi in the storage stops only when the grain moisture content drops to 14%. In the grain overwintered in the field, many toxins of this fungus often accumulate. Fungi 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 made 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, therefore the proportion of leukocytes in the blood drops sharply. Then necrotizing tonsillitis develops. Grain affected by Fusarium is stored separately from food and fodder and is used for technical purposes.

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

Aflatoxins, affecting the liver and having 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 penicilli.

Ochratoxins also damage the liver and are carcinogenic. 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 food from them is to exclude grain mold.

Defective grain is also considered to be damaged by self-heating and violations of drying regimes.

Grain quality indicators for a specific purpose are: grain nature of wheat, glassiness, gluten.

The nature of grain is understood as the mass of the specified 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. The nature is of great importance, since it indirectly characterizes one of the main indicators - grain fulfillment.

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

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

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

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

For example: one batch of wheat weighing 300 tons at a nature of 800 g / l has a grain mass volume of 300 / 0.80 = 375 m 3, the second batch of 300 tons at a nature of 730 g / l has a grain mass volume of 300 / 0.73 = 411 m 3. Consequently, the volume of grain mass of low-grade wheat is 36 m 3 more and a large storage capacity will be required to store this batch.

Grain vitreousness is one of the most important indicators of grain quality. The concept of "vitreousness" is based on the visual perception of the appearance of the 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 glassy, and soft wheat is different, depending on the variety, geographic and soil factors, agricultural technology, etc.

3. Gluten is a complex of protein substances of 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 baked bread. The content of crude 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 documents.

Implementation of laboratory control over the quality of grain accepted for storage

Cereal bread is a raw material that is stable in storage under proper conditions. The bulk of the grain is stored in elevators - large, fully mechanized granaries. The grain storage tanks are vertically placed reinforced concrete silo cylinders 6-10 m in diameter and 15-30 m high. Inside the silos, at a distance of 1 m from each other in height, thermocouples are mounted to determine the temperature of the stored grain embankment. The thermocouple wires are brought out to a single control panel, and the operator who monitors the safety of the product can at any time find out the temperature of the grain mass at almost any point in the silo. In addition, each silo is equipped with an active ventilation unit - a device for blowing air through the thickness of the stored grain. The grain arriving at the elevator after laboratory analysis is combined by weight into large batches corresponding to the silo capacity (from 300 tons to 15 thousand tons). At the same time, mixing of grain belonging to different types and subtypes is not allowed, since they have different baking properties. Do not mix grain with different moisture content and contamination. Separately from healthy grain, grain contaminated with barn pests and defective grain - frosty, sprouted, smut, wormwood, etc., are stored and processed.

Cleaning of the grain mass from impurities is carried out immediately after it enters the granaries. Weed seeds, vegetative organs of plants have a higher moisture content, the smell of odorous weeds is partially adsorbed by the grain, and the longer they are in contact, the more grain can spoil. In addition, it is not economically feasible to spend additional energy on drying impurities and to occupy storage volumes by storing them.

However, the complete cleaning of the grain mass from impurities is not carried out on the elevators; this is carried out by processing enterprises. Drying grain is a critical technological operation before storing it. Drying grain with warm dry air gives optimum results. However, drying with air mixed with flue gases is more economical. In this case, the quality of the grain will largely depend on the type of fuel. It is not recommended to use wood that gives the grain a smoke smell. Coal, especially containing a lot of sulfur, forms sulfur dioxide when burned, which can be partially absorbed by the grain and degrade the quality of gluten. In addition, the flue gases generated during the combustion of coal contain an increased amount of polycyclic aromatic hydrocarbons, in particular benzpyrene, which has carcinogenic properties. The optimal types of fuel that do not pollute the grain with benzopyrene are oil products and gas.

The temperature of the grain during drying should not exceed 45 "C. Overheating of the grain leads to a deterioration in the quality of gluten up to its complete denaturation. The activity of enzymes also decreases.

During one drying step, more than 3 - 3.5% moisture cannot be removed from very wet grain, therefore, grain with a moisture content of more than 17.5 - 18% is dried in several steps. Breaks between the drying stages are necessary to redistribute moisture from the inner parts of the weevil to the surface, otherwise the surface layers of the grain crack, which leads to a deterioration in preservation, the yield and quality of the finished product decrease. After drying, the moisture content of the grain should not exceed 14%.

The elevator is equipped with a laboratory, which evaluates the quality of grain; a working tower, where grain cleaning and drying equipment is concentrated, as well as an installation for receiving and dispensing grain.

The quality of grain taken to elevators and warehouses is systematically monitored: the temperature of the grain, the temperature of the outside air, the color of the grain, the presence of harmful grain reserves.

The temperature of the grain in the silos of the elevator is measured by remote control units (DKTE). During the summer period, the temperature of the stored grain should not exceed +5 - + 10 ° С.

Temperature in warehouses and on sites is measured with thermal rods and temperature probes. Each warehouse is divided into sections of approximately 100 m 2. Each section is assigned its own permanent number. Each section should have from 3 to 5 thermal rods. The rods are installed at different levels: upper - at a depth of 30-70 cm; in the bottom - 30-50 cm from the floor.

The height of the rash in warehouses and piles should be no more than 1.5-2.0 meters. After each measurement, the rods are moved within the section at a distance of 2 meters from the previous point, changing the immersion level.

With the onset of spring, it is necessary to check the temperature of the top layer of the grain and from the south side of the warehouse. When the temperature rises rapidly, the grain must be cooled urgently. Conduct active ventilation.

Checking seeds for pest infestation of grain stocks is carried out at a grain temperature below + 5 ° C - once a month; above + 5 ° С - 2 times a month. GOST 12586.4-83

The infection is checked in layers, each cut separately. If pests are found, it is urgent to take measures to eliminate them: degassing and gasification.

The degree of infestation is determined on the basis of 1 kg of grain. Ticks are scanned on black glass, beetles on white surfaces.

When laying seeds of grain, various crops for storage, as well as after cleaning (through separators), drying, active ventilation and before shipment, a full technological analysis is carried out: moisture, contamination, organoleptic indicators (smell, color, taste), natural weight, purity. The germination capacity of stored seeds is determined by KSL - at least once every 3 months.

The results of all observations are recorded in special journals about the quality of grain and its processing. Also, the elevator should have silo boards with a picture of the diagrams of silos and bunkers of the elevator tower. The board indicates: the culture, the date of the bookmark, the class, which was processed. Before the start of receiving grain, all receiving lines of the enterprise must be put in good condition and prepared for work: all weighing equipment and weighing devices must be checked; unloading devices, mechanisms, machines and devices must correspond to the type and size of vehicles; silos are inspected, cleaned, disinfected to receive a new crop; grain dryers and cleaning machines are being overhauled.

The plan for receiving and placing grain of the new harvest along all technological lines of the enterprise is drawn up no later than a month before the start of harvesting. During the entire storage period of grain, systematic control over the quality and condition of each batch is carried out: temperature, humidity, contamination, odor, color, etc. To measure the temperature of grain, electrothermal installations for station temperature control of the M-5 type are used. The temperature of grain in warehouses is measured using a thermal rod with a technical thermometer.

To determine the moisture content of grain during implementation and post-harvest processing, a VP-4 moisture meter is used.

To monitor the temperature of grain in warehouses, its surface is conventionally divided into sections with an area of approximately 200 m2 and three thermal rods are installed in three levels. After the next measurement, they are moved in a staggered manner by 2 meters within the section. In the silos of the elevator, the grain temperature is measured using remote control using the DKTE installation.

The grain temperature is checked in freshly harvested grain; dry and medium dry - once every 5 days; wet and damp - daily.

The rest of the grain: dry and medium dry - once every 15 days; wet and damp - 1 time per 5 days.

The timing of the check is set by laboratory technicians and foremen of the sections, depending on the highest temperature found in the layers of the grain embankment. When laying grain for storage, its full technical analysis is carried out once a month for the average sample from a homogeneous batch, which is stored for 1 month from the date of analysis for control.

Checking for pest infestation of grain stocks at a grain temperature of + 5 ° and below is carried out once a month; above + 5 ° - 2 times a month.

The results of all observations are recorded in laboratory journals.

The procedure and methods for the examination of wheat grain

The legal basis for the examination is the Federal Law “On Protection of Consumer Rights”. "The Law on the Protection of Consumer Rights" regulates the procedure for the examination, the period for the examination of the goods. The legislator establishes that the examination of the goods in accordance with paragraph 5 of Art. 18 of the Law is carried out within the time frame established by Art. 20, 21 and 22 of this Law to meet the relevant consumer requirements. Earlier, a similar conclusion followed from a comprehensive interpretation of the requirements of the Law, today, a direct indication of the timing of the examination excludes unnecessary disputes on this issue. If a demand is made to replace the goods, the examination must be carried out by the seller within a period of not more than 20 days, and on termination of the contract and refund of money - 10 days from the date of the specified demand. The consumer has the right to be present during the examination of the goods and, in case of disagreement with its result, to challenge the conclusion of such an examination in court. Your desire to participate in the examination must be stated in a written application when presenting your demand to the seller when transferring goods of inadequate quality. , Expertise (from the French. Espertise, from the Latin. Espertus - experienced) - the study by a specialist-expert of any issues, the solution of which requires special knowledge in the field of science, technology, economics, trade, etc.

Expertise - an independent study of the subject of expertise (goods), carried out by a competent specialist (expert) on the basis of objective facts in order to obtain a reliable solution to the problem. Namely - checking the compliance of the received batch with the terms of the contract / agreement in terms of quantity, quality, packaging, labeling of goods; determination of the quality level of the goods by consumer properties and / or by the level of defectiveness; identification of the reasons for the formation of defects and / or the percentage of reduction in quality for the presence of defects; identification of goods, etc. The purpose of the commodity examination of wheat grain is to obtain new information about the fundamental characteristics of the goods in the form of an expert opinion, which cannot be obtained by objective methods, but is necessary for making certain decisions. The purpose of the commodity examination should be formulated by its initiator, that is, the customer, taking into account the problem that has arisen. The expert must solve a number of special and general tasks to achieve the goal.

The general goals are:

Determination of the grounds for the examination; establishment of requirements for the object and conditions of examination;

Formulation of questions that need to be answered as a result of the examination;

Study of the object of expertise;

Analysis and evaluation of the data obtained during the examination for drawing up a conclusion; documenting the results of the examination.

The examination of goods is faced with very specific tasks, which are formulated taking into account the characteristics of the object of examination:

determining the degree of product novelty, competitiveness, etc .;

determination of the conformity of the quality of goods to the current state standards, contractual conditions between the supplier (seller) and the consumer (buyer).

The expert examination establishes deficiencies in the quality of goods, works, services, as well as the reasons for their occurrence. For any examination of goods, experts should use, first of all, regulatory documents on standardization and certification. When conducting an examination, experts must be guided by the Civil Code of the Russian Federation (Articles 465, 466, 483, 521). Previously, the expert must familiarize himself with all regulatory documents on metrology, trade, veterinary medicine, sanitation and hygiene.

The examination of the quality of grain is carried out on the basis of determining the organoleptic and analytical indicators, using the methods set forth in the state standards. Determination of organoleptic indicators is carried out in accordance with GOST R 52554− 2006 "Wheat, technical conditions", GOST 10967−90 "Determination of odor and color". The class or type of grain is determined by the worst value of one of the indicators of grain quality. The standards for grain also set restrictive norms depending on the purpose; for food purposes, processing into cereals, flour, for the production of compound feed.

The color and appearance are determined by examining the sample in order to establish the type (culture) of the grain, its type and, in part, to identify its condition. Grain is fresh, normally ripe, harvested and stored under favorable conditions, has a well-defined color, characteristic of a given culture, type, variety, and a smooth shiny surface. Grains that have been soaked and moistened are usually dull, whitish, and the grains of membranous crops are darkened. The spoiled grain is clearly darkened, patchy, sometimes with mildew spots on the surface. Color and appearance are best determined in diffused daylight by comparing the test specimen with the specimens normal for the grain of a particular culture and type.

The smell of grain depends on the volatile substances in it. There are very few of them in normal grain and the smell of grain is not perceptible. The smell of grain changes for two reasons: either as a result of its deterioration (self-heating, rotting, mold), or as a result of the adsorption of foreign odorous substances by the grain. The following odors are considered abnormal, not characteristic of full grain grains: malt - arises as a result of self-heating of grain and subsequent drying. The smell of rotten grain is very vaguely reminiscent of the smell of malt, that is, sprouted and dried grain; musty - occurs as a result of spoilage and decomposition of grain substances, as well as when it is stored in poorly ventilated musty rooms, where it adsorbs odorous substances released by mold; moldy (mushroom) - caused by the development of other types of molds in the grain. Most often, it occurs in raw cold grain, where there was not self-heating, but mold; putrefactive - caused by bacterial decomposition of grain proteins, accompanied by the release of protein breakdown products - skatols, indoles, mercaptans; foreign - odors arising from the adsorption of volatile substances from the environment by the grain: essential oils of wormwood, garlic, the smell of oil products, smoke, etc.

Any foreign smell is considered unacceptable. To determine the smell, a small amount of grain is warmed by breathing. If a little grain (5-10 g) poured into a glass, pour hot water (60-70 ° C), close and leave for 2-3 minutes, then drain the water, its smell is felt better.

Normal grain taste is poorly expressed. Usually it is bland, slightly sweetish, sometimes with a flavor specific to the grain of this culture. The taste is determined by chewing about 2 g of clean, ground grain. Rinse the mouth with water before each determination. If the grain has a wormwood smell, then it is ground together with impurities. Grains with a bitter, sour or clearly sweet taste, as well as with any off-flavors not typical for this grain, are considered to be of poor quality. Bitter taste can result from grain deterioration during storage, i.e. the result of the decomposition of grain fat and the formation of bitter substances. In addition, in the presence of an admixture of wormwood, the grain sometimes perceives a bitter substance - absetine and also acquires a bitter taste. The sour taste is due to the development of microorganisms that cause various types of fermentation, and the formation of certain organic acids. Sprouted or apparently unripe grain has a sweet taste. Foreign tastes can also be caused by the adsorption of foreign substances, the development of granary pests, etc.

The analytical indicators characterizing the properties of the grain mass include the following: moisture, weediness, pest infestation and bulk density (nature) of grain. The moisture content of the grain is determined by the formula: without preconditioning X (%)

where m0 is the mass of a sample of ground grain or rods before drying, g;

m1 is the mass of a sample of ground grain or rods after drying, g.

The moisture content of the grain when determined with preconditioning X 1 (%) is calculated by the formula

where m2 is the mass of the sample taken before preconditioning, g;

m3 is the mass of the sample after conditioning, g.

The admissible discrepancy between the results of two parallel determinations should not exceed 0.2%. The average value of the results of parallel measurements is taken as the final result. For control determinations of moisture, the permissible discrepancies between the control and initial determinations should not exceed 0.5%. Otherwise, the result of the control determination is taken as the final one. The nature of the grain (density indicator) is determined on a special scale - purkah. The nature is an indicator of the density of the grain mass and changes in inverse proportion to its wellness. In addition to wellness, the bulk density depends on the structural features of the grain, its shape, specific gravity, as well as the composition of impurities and moisture. Determination of the nature is necessary to calculate the capacity of warehouses and bins, the need for containers and vehicles. By nature, one can indirectly judge the wellness of wheat grain. Weed and grain impurities are determined in accordance with GOST 13586.281. Harmful impurities have a bad effect on the quality of wheat grain, they can threaten the health of the consumer, if poisonous substances get into the raw materials.

The given indicators and methods of examination of the quality of wheat grain are provided for by the current standards, which are guided by the procurement and supply of wheat grain. In addition, the quality of the grains forming the batch is characterized by physical and chemical indicators: absolute mass (1000 grains weight), uniformity, filminess, vitreousness, ash content, fiber and protein content and some other indicators of composition and biochemical properties that are not provided for by the standards.

Examination of the quality of wheat grain is extremely important to ensure the production of products (flour, cereals) in the greatest quantity and high quality, since the yield and quality of flour and cereals are inextricably linked with the properties of the feedstock - wheat grain.

Like any agricultural product, grain has its own quality characteristics that determine how suitable it is for human use. These parameters are approved by GOST and are evaluated in special laboratories. Grain analysis allows you to determine the quality, nutritional value, cost, safety and scope of use of a particular batch or variety.

The test results depend on three components:

the genetic characteristics of the crop from which the crop was harvested;
growing conditions and transportation technology;
storage.

The approved state unit of quality assessment is the batch from which samples are taken for analysis.

Basic analysis parameters

The parameters determined using grain are divided into 3 large groups:

quality indicators - a set of physical, chemical and biological properties that characterize the degree of usefulness and suitability of grain for technical and agricultural use;
safety indicators - assess the presence of chemical impurities harmful to health, characterize the environmental friendliness of grain;
content of GMO (genetically modified samples).

The first group is the most extensive and is a mandatory component of checking grain consignments. The quality assessment includes 2 types of grain analysis indicators:

organoleptic - assessed using the human senses;
laboratory or physicochemical - are determined using specific techniques and technical equipment.

Among the laboratory parameters, there are basic (mandatory for a specific culture) and additional ones. Each grain quality characteristic has a specific name and determination method.

Deciphering grain analysis

Parameter	Characteristic
Humidity	The percentage of water in the grain.
Temperature	It is measured at different points at the depth of the grain mass. Normally, it should not be too high or grow quickly.
Nature	It characterizes the mass of one liter of grain, expressed in g / l.
Size	Determines the dimensional parameters of the grain. This group of indicators includes the mass of 1000 grains, specific gravity, as well as the length, width and thickness of the seed.
Vitreousness	It characterizes the degree of transparency of the grains.
Filminess	Determined for cereal crops (oats, barley, rice, buckwheat, etc.). It characterizes the percentage of films or shells in the grain mass. The higher the hulliness, the lower the yield of the finished cereal.
Clogging	Shows the percentage of impurities to the total grain weight.
Germination	Ability to give normal shoots in natural conditions for a particular culture.
Germination energy	The percentage of kernels that have sprouted within a specified amount of time.
Falling number	It characterizes the degree of grain germination (the higher the indicator, the lower the baking
Ash content	The amount of mineral (inorganic) substances in the grain. It is determined by weighing the mass remaining after complete combustion of the ground grain at a temperature of 750-850 ° C.
Evenness	It characterizes the grain size uniformity.
Contagion	The number of pests in the culture (bugs, turtles, etc.), is expressed in the number of live individuals per 1 kg of grain.

For wheat, grain is additionally analyzed for gluten and protein content.

Grain quality assessment is an integral part of the control of agro-industrial products and forms the basis of scientific research on crops that accompany the development of new varieties or the study of the influence of various environmental factors on grain plants (fertilizers, soil, pests, phytohormones, etc.).

Additional parameters for analyzing grain quality include chemical composition, enzyme activity, microorganism content, etc.

seed grain

To analyze grain for sowing qualities, 3 average samples are isolated from the batch by the quartering method, which are used to determine different indicators:

sample 1 - purity, germination, weight of 1000 seeds;
sample 2 - moisture and pest infestation;
sample 3 - the degree of disease damage to seeds.

Based on the results of the analysis, a conclusion is made on the sowing qualities of the seeds, which is included in the corresponding inspection document.

Germination is determined by placing 100 grains in conditions suitable for germination for 3 days. At the same time, the number and uniformity of seedlings are assessed. To quickly identify dead grains, the Lecon method is effective, which gives a result within a few hours. Living grains are identified by the color change that occurs when oxygen is absorbed from a tetrazolium salt solution. In dead seeds, respiration is absent.

Organoleptic evaluation

The main organoleptic indicators are color, shine, taste and smell, on the basis of which a conclusion is made about the good quality and freshness of a batch of grain. The color should be uniform, the surface of the seeds should be smooth and shiny. The presence of extraneous odors (not characteristic of culture) indicates the spoilage or violation of the storage technology.

The following are also evaluated by eye:

shape and size;
uniformity of the batch;
weediness;
shell state.

The color, smell and taste of the beans are checked for compliance with a specific biological variety. Sensory analysis is superficial and approximate, but can reveal serious abnormalities. The parameters of the test sample are compared with the standards available in the laboratory.

Assessment of weediness and infestation

Impurities are divided into 2 large groups: grain and weed. The latter is subdivided into 4 types:

mineral - particles of inorganic nature (pebbles, sand, dust, pebbles, etc.);
organic - third-party particles of organic origin, to a greater extent - vegetable (pieces of spikelets, leaves, etc.);
weed - seeds of foreign crops;
harmful - fruits or seeds, which contain substances that are toxic to humans.

Defective (different from normal) seeds in a batch are called impurities. They can also be used for technological processing, although they give a product of lower quality. To reduce the content of trash impurities, the grain is cleaned on production machines.

The mass of average samples for analysis of grain for weediness is 20-25 grams. The proportion of impurities is determined as a percentage.

Infection can be overt and latent. In the first case, the pests are separated from the sample using a sieve, and in the second, each grain is split and inspected (sample size - 50).

Chemical analysis

This analysis belongs to the category of additional and involves the study of the chemical composition of the grain. In this case, the percentage of the following components is determined:

proteins;
lipids;
carbohydrates (including starch and fiber);
vitamins;
minerals (macro-, micro- and ultramicroelements).

The grains also include the determination of ash content.

These parameters show the nutritional value of a particular variety, and sometimes also the technical value. For example, a large amount of lipids in sunflower seed indicates a high suitability of the raw material for oil production.

Determination of certain components of the composition is a key quality factor. So, when analyzing wheat grain, the percentage of protein is necessarily determined. This indicator characterizes not only the nutritional value, but also the baking properties, as it correlates with the glassiness and quality of gluten.

Equipment

There are a huge number of devices for the analysis of grain, among which one can distinguish specialized (developed for laboratory assessment of grain products) and general. The latter include devices for physical and chemical measurements, equipment for working with reagents.

The standard laboratory kit for grain analysis includes:

scales of high precision;
weights;
devices for determining the properties of gluten;
watch glasses and Petri dishes;
sieves with cells of different diameters;
porcelain stupas;
desiccator;
mill;
moisture meters;
temperature measuring device;
laboratory glassware (flasks, bottles, etc.);
drying chamber;
chemical reagents.

The set may also contain narrow-profile devices, for example, peelers, with the help of which the filminess is determined. The presence of metal-magnetic impurities is detected using milliteslameters.

Some instruments replace manual methods for determining some parameters. For example, vitreousness can be ascertained using a diaphanoscope. Automating grain analysis significantly reduces subjective factors and saves time.

There are also devices for complex analysis, which replace the multi-step process of determining different parameters, which requires a whole set of instruments and reagents. However, the functionality of such devices is still limited.

Currently, the assessment of the quality of grain products is a combination of manual and automated methods of grain analysis, the ratio of which is determined by the technical support of a particular laboratory and a set of verified indicators.

Determination of moisture

Moisture is one of the key parameters of grain quality, which determines not only its nutritional value, but also storage conditions.

There are 2 ways to analyze grain moisture:

using an electric drying cabinet (SES) - it consists in drying the ground grain sample and comparing the weight before and after the procedure;
with the use of an electric moisture meter - determination of the degree of humidity by electrical conductivity, a sample of grain is placed into the device under a press.

The second method is economical in terms of time, but less accurate. In the case of too high humidity (more than 17%), the test sample is pre-dried.

Depending on the percentage of water, there are 4 degrees of grain moisture:

dry (less than 14%);
medium dryness (14-15.5%);
wet - (15.5-17%);
raw - (more than 17%).

The given percentages are acceptable for the main grain crops (rye, oats, wheat, etc.).

Moisture content of more than 14% is considered elevated and undesirable, since it leads to a decrease in the quality and germination of grain. Each crop has its own water content standards, developed taking into account the characteristics of the chemical composition of the seeds.

Filminess

The assessment of the filminess includes 2 stages:

counting the number of casings or films;
determination of the percentage mass fraction of the shells.

The second indicator is the most important. To determine it, the grains are preliminarily freed from the shells using a peeling machine or manually, and then the cereals and the film mass are weighed separately. Finally, compare the weights of the cleaned and uncleaned samples.

Vitreousness

The degree of transparency depends on the ratio of protein to starch. The higher the content of the latter, the more mealy (starchy) and turbid grain. Conversely, a large amount of protein increases the clarity of the seed. Consequently, the vitreous value reflects the nutritional value and baking quality of the grain. In addition, this indicator is associated with the mechanical and structural properties of the endosperm. The higher the glassiness, the stronger the grain and requires more energy consumption for grinding.

There are 2 methods for determining this parameter: manual and automated. In the first case, the transparency is assessed by eye or using a diaphanoscope. A sample of 100 grains is analyzed. Each seed is cut in half and classified into one of three vitreous groups:

mealy;
partially vitreous;
vitreous.

The total number of grains from the last two categories is the total vitreousness (only half of the partially vitreous seeds are included in the total). The check is carried out 2 times (the discrepancy between the results should not exceed 5%).

There are also automated diaphanoscopes that simultaneously determine the vitreousness of seeds placed in a cuvette. Some devices do not even require pre-cutting the beans.

Falling number

Falling number is an indirect indicator of the degree of germination, determined on the basis of the level of autolytic activity of the grain. The latter is the result of the action of the enzyme alpha-amylase, which breaks down the starch of the endosperm to simple sugars, which are necessary for the development of the embryo of the seed. Naturally, this leads to a significant decrease in the baking quality.

Autolytic activity is determined using special equipment (Falling Number, PPI, PPP, etc.). The method is based on enzymatic liquefaction (under the action of alpha-amylase) flour suspension, gelatinized in a boiling water bath.

GOST grain analysis

All components of product analysis are strictly regulated and spelled out in the relevant standards. GOST contains quality standards, equipment requirements and methods for determining each indicator. The grain analysis results are considered reliable only if received in accordance with the established instructions.

According to GOST, the classes of grain crops are determined, for each of which the corresponding values of the quality parameters are prescribed (the so-called restrictive norms). 5 classes are allocated.

The class determines the nature of processing and use, storage characteristics and market value of grain.

Express grain analysis using IR spectroscopy

With the help of IR spectroscopy, you can quickly and accurately determine:

humidity;
protein and gluten content;
the amount of starch;
nature;
density;
oil content;
ash content.

For the main parameters of grain analysis, the error does not exceed 0.3%.

Complex analyzers are based on diffuse reflection of light with a wavelength within the near infrared spectrum. This significantly saves time (analysis of several parameters is carried out within a minute). The main disadvantage of the express method is the high cost of equipment.

Analysis for the content and quality of gluten

Gluten is a dense and viscous rubbery mass formed after water-soluble substances, starch and fiber are washed out of the ground grain. Gluten contains:

proteins gliadin and glutenin (80 to 90% dry matter);
complex kg carbohydrates (starch and fiber);
simple carbohydrates;
lipids;
minerals.

Wheat contains from 7 to 50% of crude gluten. Indicators over 28% are considered high.

In addition to the percentage, when analyzing grain for gluten, four parameters are assessed:

elasticity;
extensibility;
elasticity;
viscosity.

The most important indicator is firmness, which characterizes the baking properties of wheat. To determine this parameter, a gluten deformation index (IDC) device is used. The sample for the analysis is a ball rolled from 4 grams of the test substance and previously kept in water for 15 minutes.

The quality of gluten is a hereditary trait of a particular variety and does not depend on growing conditions.

The analysis of wheat grain for gluten content is carried out strictly in accordance with the standard, since the slightest error can greatly distort the result. The essence of the method consists in washing the analyte from the dough mixed from wheat meal (crushed and sifted grains). Washing is carried out under a weak water jet at a temperature of + 16-20 ° C.

The state of the grain mass and its qualitative characteristics, normalized by the current normative and technical documentation, change depending on the intensity of the physiological processes taking place in it and the environmental conditions. Therefore, in order to prevent the development of undesirable processes in the grain mass, to ensure a decrease in storage losses and processing costs, they organize a systematic monitoring of it during the entire storage period.
The indicators monitored during storage of grain masses include: temperature, humidity and content of impurities, infection, odor and color, etc., and in batches of seed grain - also its germination and germination energy.
Quality control and condition of food and feed grains during storage. From the moment the grain arrives at the enterprise, a systematic control over the quality and condition of each batch is organized.
An increase in the grain temperature during storage (the most important and most sensitive indicator of the state of the grain mass), independent of changes in the temperature of the atmospheric air, indicates the activation of processes and the onset of self-heating.
To measure the temperature of grain in elevators, electrothermometric installations with remote control of the types DKTE, MARS M-5, etc. are used, and to measure the temperature of grain in warehouses, temperature probes with technical thermometers and a temperature indicator of the ITE type are used.
An increase in grain moisture in individual layers of the embankment can occur for the following reasons: as a result of the activation of respiration of grain and other components of the grain mass, as a result of interaction with the air of the environment, as a result of the phenomenon of thermal and moisture conductivity. Therefore, when areas of grain embankment with high humidity are found, urgent measures are taken to level it.
For the express method for determining the moisture content of grain during placement and post-harvest processing, moisture meters of the following brands are used: VP-4, VP-4M, such as Kolos-1, TsVZ-Z, IVZ-M, Fauna, etc. More precisely, grain moisture can be determined by a standard drying method.
To monitor the temperature of grain in warehouses, its surface is conventionally divided into sections with an area of approximately 200 m2 each. When the height of the embankment in the warehouses is more than 1.5 m, three thermal rods are installed in each section at different levels (the upper one - at a depth of 0.3 ... 0.5 m from the surface, the middle and lower ones - at the floor). When the height of the embankment of seeds is not more than 1.5 m, the temperature is determined in two layers: upper and lower. After each determination of the temperature of the seeds, the thermal rods are rearranged at a distance of 2 m from each other in a staggered manner, changing the level of immersion of the rod.
In silos of elevators not equipped with remote control devices, the temperature is measured with thermal rods at a depth of 0.5, 1.5 and 3.0 m; if necessary, to control the quality and condition, the grain is transferred to free silos (in their absence, the current Storage Instruction allows no more than 10% of grain to be released from the silo, which is then returned to the same silo), while controlling the temperature, humidity, smell, color grain and pest infestation.
If signs of pest infestation are detected in the grain released from the silo, measures are taken to prevent the spread of pests through transport equipment. In particular, after moving the contaminated grain, the conveyor must be turned around at idle speed, while the belt must be cleared of adhering debris and insects. Cleaning is best done at the end of the conveyor. Remains of grain from the bucket elevator shoes must be removed, and the place near the bucket elevator must be wet-processed. If spills form, they should be immediately removed, and the place and surrounding space should be immediately treated with karbofos or dichlorvos. When taking measures with regard to contaminated grain, follow the current Pest Control Instruction.
In metal silos, the temperature control of grain in a dry state at a temperature above 10 ° C is carried out once every 3 days, at a grain temperature of 10 ° C and below - once every 7 days. The timing of the check is set according to the highest temperature recorded in individual layers of the grain embankment.
A complete technical analysis of grain of various crops is carried out: when laying for storage; after cleaning, drying, active ventilation; during storage (once a month for an average sample taken from a homogeneous batch); before shipment.
When analyzing for contamination, attention should be paid to the appearance of previously unseen components, for example, darkened, corroded, moldy and other grains; their appearance is evidence of the development of microorganisms, pests, as well as the process of self-warming.
Changes in color and odor, loss of grain shine during storage are the harbingers of deep biochemical and technological changes. In particular, the appearance of a specific alcoholic smell indicates intensive respiration of the grain mass, and the appearance of a moldy smell indicates the active development of microorganisms.
In all cases, measures are taken to stop undesirable processes: actively breathing and heating grain is ventilated for cooling purposes, and grain with a moldy smell (without increasing the temperature) is dried in grain dryers.
Checking grain for infestation with grain pests is carried out: at a grain temperature of 5 ° C and below - once a month; at temperatures above 5 ° C - 2 times a month.
The state of corn on the cob by moisture and pest infestation is determined at least 2 times a month, and its infestation with molds and bacterial diseases is determined at the time provided for measuring the temperature by breaking individual ears and determining the contamination of grain, especially its embryo.
Quality control and condition of seeds during storage. Ensuring the preservation of the quality of seeds from the moment they arrive at the grain-receiving enterprise is associated with the need for systematic control over the temperature and humidity of seeds and ambient air, organoleptic quality indicators (smell and color of seeds), infection and germination. Control is carried out for each individual batch (stack, silo, warehouse, etc.). When storing large lots of seeds in bulk in warehouses, the surface of the embankment is conventionally divided into sections (no more than 50 m2 each), and each of them is monitored.
The temperature of the seeds in the warehouse is determined in the same way as the temperature of food and feed grains. The temperature in silo-type tanks is measured with remote control installations of types DKTE, MARS M-5, etc. The frequency of temperature determination is set depending on the highest temperature detected in individual layers of the seed embankment (Table 11.4).

When storing seeds packed in bags, temperature measurements are carried out in accordance with table. 11.4, equating them to dry.
An increase in the temperature of the seeds, not associated with an increase in the temperature of the atmospheric air, is a signal for their immediate cooling or drying; the temperature of such seeds is monitored daily. This is especially true for batches of seeds, which, in terms of moisture content, cannot be attributed to one class or another.
The moisture content of seeds stored in bulk in warehouses and silos is monitored at least 2 times a month, as well as after each movement and processing. Moisture content is determined from samples taken from each section of the warehouse in accordance with the standards for sampling methods, and in the silo - in the upper layer of the embankment at a depth of 3 m.
Checking seeds for infestation by insects and mites and determining organoleptic indicators is carried out depending on the temperature and moisture content of the seeds in the terms given in table. 11.5.

The germination capacity of stored seeds is checked at least once every 4 months, as well as before disinfection from insects and ticks (no earlier than 15 days) and after degassing (after 15 ... 30 days).