Introduction

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

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

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

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

Corn. Main indicators of grain quality

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

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

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

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

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

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

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

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

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

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

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

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

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

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

grain quality indicator flour

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

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

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

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

The quality of each batch of grain is established on the basis of the results of a laboratory analysis of an average sample made up of recesses taken from the batch.

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

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

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

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

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

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

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

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

Fig.1.

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

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

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

Fig.2.

The test sample of grain is placed in the middle of the frame in a square hole closed by a valve located on back wall framework.

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

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

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

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

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

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

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

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

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

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

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

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

Need to pay Special attention on the first sensation, as it is usually the most correct.

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

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

Odors associated with changes in grain condition include:

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

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

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

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

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

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

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

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

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

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

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

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

For better recognition of odors, it is recommended to warm a handful of grain with a breath or warm it in a cup under an electric light bulb, on a battery or over boiling water for 3-5 minutes. Grain can be poured into a glass, pour hot water\u003d 60-70 ° C, cover the glass with glass and leave for 2-3 minutes, then drain the water and determine the smell of grain.

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

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

vitreousness characterizes the grain structure, the relative position of tissues, in particular starch granules and protein substances, and the strength of the bond between them. This indicator is determined by transillumination on a diaphonoscope and counting the number of grains (in%) of vitreous, semi-vitreous, mealy consistency.

Grain is considered vitreous, if the endosperm is densely built, shiny at the break, completely vitreous or the powdery part in it makes up no more than 25% of the cross section of the grain. Such grain breaks into large particles during crushing and almost does not produce flour.

At mealy endosperm grains are completely farinaceous (starchy) or vitreous is not more than 25% of the cross section. Grain with such a consistency is easily cut and crumbled. Grains with an intermediate consistency are semi-vitreous.

By total vitreousness, the following groups of grains are distinguished: highly vitreous- glassiness above 70%, medium vitreous - 40- 70, low vitreous- below 40%.

Fall number characterizes the activity of a-amylase, the degree of grain germination. During grain germination, part of the starch turns into sugar, while the amylolytic activity of the grain is enhanced and baking properties deteriorate sharply.

The state of starch in the grain is associated with the degree of activity of a-amylase, which increases as the grain germinates.

The "falling number" characterizes the activity of a-amylase according to the degree of dilution of the water-flour suspension and is measured by the duration of the immersion of a stirrer calibrated by mass.

The lower the index, the higher the degree of grain germination.

A grain of wheat is considered complete when the fall number is 201c and above, i.e. with medium and low activity of a-amylase.

Grain with a high activity of a-amylase can be used at a falling number of 80 ... 150 s for sub-sorting to full-fledged grain in an amount of 10 ...

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

The quality of gluten is measured on the IDK device in conventional units, and depending on

From the readings of the device, gluten is classified into one of three quality groups:

Group I - gluten with good elasticity, it is possible to obtain dough with good elasticity from it.

dimensional stability and sufficiently loosened, which allows you to get bread with a large

volume and good porosity;

Group II - gluten with good or satisfactory elasticity, bread is usually

is obtained with a lower volume yield than with quality group I, but in most cases

benign;

Group III - gluten is very strong (crimped bread, with cracks in the upper crust,

coarse crumb) or very weak, floating (bread spreading with low volume,

dense crumb).

gluten quality - by measuring its elastic properties on the IDK device (gluten deformation meter). The principle and method incorporated in the IDK device are based on the measurement of the “value of residual deformation of a gluten sample after exposure to a calibrated load for a specified time (30 s).

To assess the acidity of grain, the determination of active acidity is usually not used, since grain substances have a buffering capacity. Grain quality is characterized by titratable acidity. It is measured in degrees of acidity. The degree of acidity is equal to one milliliter of normal alkali, which has gone to neutralize 100 g of ground grain.

To determine the acidity of the grain, an aqueous mash of ground grain is used or: in some cases, water, alcohol and ether extracts.

By increasing acidity (taking into account other indicators), one can judge the degree of freshness of grain and flour. As a result of self-heating or souring of grain, flour and cereals, the content of acetic and lactic acids increases, and when fats deteriorate as a result of hydrolysis, free fatty acids accumulate, which turn into alcohol and ether extracts, which allows them to be analyzed.

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

Nature- (volumetric mass) is the mass of the established volume (for example, 1 l) of grain, expressed in grams.

The larger the nature of the grain, the better its quality, and vice versa.

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

All sorts of impurities, usually lighter than the grain, degrade the quality of the grain and reduce his kind. Increased grain moisture also lowers this indicator. It should be noted, what bulk density can sometimes give an incorrect estimate quality grains. So. for example, small or broken grains, as well as various small heavy impurities of an organic or inorganic nature, located in the gaps between the grains, increase the value of nature, at the same time worsening the quality of the grain. Determination of the nature of the grain must be accompanied by additional its characteristics, at least based on external examination.

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

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

The quality of grain is affected by indicators characterizing its consumer value. These include: fineness, weight of 1000 grains, unevenness (uniformity), density, filminess.

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

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

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

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

Mayonnaise is a multicomponent system, and the qualitative and quantitative composition of the ingredients determines its functions and properties. In addition to vegetable oil and water, mayonnaise contains emulsifiers, stabilizers, structure formers, as well as flavoring, functional and other food additives that give mayonnaise a different taste, aroma, nutritional and physiological value and allow creating a wide range of these products.

Fat bases. Vegetable oils are used as a fat base for mayonnaise products. These include sunflower, soybean, corn, peanut, cotton, olive. All vegetable oils for the production of mayonnaise must be refined and deodorized. The choice of the type of vegetable oil depends on the manufacturer, its capabilities. The collection of recipes for the standard technological regulations for the production of mayonnaise does not specify the type of vegetable oil, but requires its complete refining.

Emulsifiers. In the production of mayonnaise, various combinations of emulsifiers are most often used, which make it possible to obtain highly stable emulsions at their low consumption. In the production of mayonnaise, natural food surfactants (surfactants) are used as emulsifiers. As a rule, natural surfactants are protein-lipid complexes with different compositions of both high- and low-molecular emulsifying substances. Various combinations of natural emulsifiers can increase the emulsifying effect and reduce their total consumption.

In our country, the following varieties of egg products are used as the main emulsifying components: egg powder, granulated egg product, dry egg yolk. The content of egg products in mayonnaise, depending on the recipe, ranges from 2 to 6%.

Egg products for the preparation of mayonnaise are used both fresh and canned in various ways: freezing, drying in a spray dryer, salting. You can use both whole-egg raw materials and made only from yolks. However, it should be noted that according to the standard of the Russian Federation, only dried egg products (in powder or granular form) are allowed to be used.

In terms of chemical composition, egg products are a complex structure, the basis of which is a protein-phospholipid complex, while proteins are high-molecular surfactants, and phospholipids are low-molecular. A protein molecule contains regions with covalent (oil-soluble) and ionic (water-soluble) bonds. Examples are the amino acids, tryptophan and phenylalanine in the protein chain.

The protein and yolk of an egg have a different composition of proteins. The protein consists mainly of proteins, including ovoalbumin, ovoconalbumin, ovoglobulin, lysozyme, etc. These proteins determine such functional properties of the protein in the production of mayonnaise as solubility in the aqueous phase, the ability to disperse, and also bactericidal action (lysozyme). The yolk contains both proteins (vitelin, lipovitelin, livetin, phosphitin, etc.) and lipids. The most important of these are triglycerides (62%) and phospholipids (33%), which include lecithin.

Lecithin is the main emulsifying agent in egg yolk. The yolk in the composition of the recipe, in addition to the emulsifying effect, also affects the taste and color of the product.

Egg products used as emulsifiers by mayonnaise manufacturers abroad are quite diverse. These are fresh whole eggs, fresh yolks, frozen fresh whole eggs and yolks, salted pasteurized liquid yolks, etc. The legislation of various countries regulates the mass fraction of eggs in the product, as well as the solids content of egg yolk. For example, in the UK, a product must contain at least 1.35% egg yolk solids (DM). The calculation is based on the fact that the yolk is 36% of the mass of the egg and contains 51% of the DM.

A good emulsifier traditionally used in the production of mayonnaise is dried dairy products. From dairy products, skimmed milk powder, whole milk powder, dry cream, dry milk whey, dry milk product (SMI), whey protein concentrate (WPC), dry buttermilk and other dry milk products are used as emulsifiers.

Milk proteins, when interacting with emulsified fats, form a complex that is a good emulsifier.

The main fraction of milk proteins is casein complex (about 80%), whey proteins (12-17%). Whey proteins contain more essential amino acids and are more complete in terms of nutritional physiology, so whey protein concentrate is often used as a substitute for egg powder in low-calorie mayonnaises.

Casein is also used in mayonnaise in the form of sodium caseinate. So-called coprecipitates are also used - products of co-precipitation of casein and whey proteins.

When creating low-calorie and dietary varieties of mayonnaise, vegetable proteins, mainly soy, are sometimes used as emulsifiers. Soy contains significant amounts of lecithin. Soy biologically active substances have a preventive and therapeutic effect on the human body. These include easily digestible protein, B vitamins, antioxidant vitamin E, iron, phosphorus, calcium, and dietary fiber. Vegetable proteins are produced in the form of defatted flour (50% protein), protein concentrate (70-75%) and protein isolate (90-95%).

To reduce the mass fraction of egg powder in mayonnaise recipes, the possibility of replacing it with food surfactants is currently being studied, including polyglycerol and fatty acid esters (E475), 60% soft monoglycerides (E471), lactic acid and citric acid monoglycerides (E472b and E472c ). Among low molecular weight compounds, the main surfactants that can act as stabilizers are phospholipids.

Oilseed raw materials serve as a source of natural phospholipids. In the Russian Federation, one type of phospholipid products is produced - a phosphatide concentrate from vegetable oils. Recently, the drug "Lipofolk" (with a phospholipid content of about 30%) has also been developed, which is a mixture of lipid components extracted from chicken ovarian follicles.

At the Moscow State University of Food Production, a synthetic phosphoglyceride, an emulsifier FOLS, has been developed, which is a mixture of ammonium salts of phosphatidic acids with triglycerides of higher fatty acids and has a phosphoglyceride fraction content of at least 70%. The emulsifier has a high surface activity, antioxidant properties, the ability to suppress the vital activity of microorganisms, and also increase the digestibility of fats in the intestine.

To achieve a higher effect, emulsifiers in mayonnaise formulations are usually combined in various proportions. In this case, it is necessary to take into account the thermodynamic compatibility of the main classes of proteins, the regularities of phase equilibria in these systems, the behavior of proteins with changes in pH, temperature, ionic strength, and their rheological characteristics in a two-phase system.

Thus, the manufacturer can change the taste and functional characteristics of mayonnaise, their cost within a fairly wide range.

Foreign firms offer manufacturers ready-made emulsifying systems with the optimal composition of emulsifiers. So, for example, the company "NANM" (Germany) offers a series of emulsifiers with the general name "Hamultop":

Based on dairy protein products - Hamultop 031, 090, 091,160,164, etc., which are used at a dosage of 0.5-1.5%;

Based on vegetable (soy, grain, legume) proteins - Hamultop 800, 803, 804, etc.

The Stern company offers Sternpur E emulsifier for use in salad dressings, which is an isolated and active phospholipid complex isolated from raw liquid lecithin. Sternpur E is used to emulsify and stabilize emulsions, preventing bubble formation and coalescence. The emulsifier replaces mono-, diglycerides and polysorbages, far exceeds the whole egg, improves viscosity. The proposed dosage is 0.2-0.5% by weight of the emulsion.

Stabilizers. A very important problem in the production of mayonnaise is the stabilization of the emulsion. For the stability of high-calorie mayonnaises, in some cases, only an emulsifier is sufficient. And in order to give long-term stability to less stable medium- and low-calorie mayonnaise emulsions and protect them from separation (during long-term storage, when changing temperature conditions, during transportation), stabilizers are introduced into the formulations. They must increase the viscosity of the dispersion medium, preventing the aggregation and coalescence of oil droplets, i.e., they must be hydrophilic in nature.

In the production of mayonnaise, hydrocolloids are mainly used as stabilizers. In Russia, grade B corn phosphate starch, carboxymethyl starch, sodium alginate are used. Abroad, xanthan, which is a biopolysaccharide, is used to stabilize most mayonnaises. Mustard powder is a flavor additive, and the proteins it contains also provide emulsification and structure formation.

Stabilizers that meet the requirements that mayonnaise producers impose on them must:

Be compatible with other food ingredients in the product;

Provide the required consistency, which remains for a long time even during cooking, and other consumer and technological properties of the product;

Have a low concentration and adjustable rate of jelly-formation;

Be non-toxic and non-allergenic;

Have a low cost and a significant raw material base.

Thickeners. In the formulations of low-calorie mayonnaises (and sometimes medium-calorie ones containing a large mass fraction of water), thickeners-structurizers are used to increase the stability of the emulsion. These are mainly starches and their derivatives, which are obtained from various industrial raw materials: corn, potatoes, wheat, rice, tapioca. In the production of mayonnaise, both native (requiring cooking) and modified (water-soluble) starches are used.

Native starches are well dispersed in water, but do not dissolve. When heated to a temperature of 55-85 ° C, they swell, forming a paste - a starch paste. Therefore, in mayonnaise emulsions, such starches are used as structure formers after heat treatment. The pastes formed from native starches are not sufficiently stable, prone to syneresis, and are affected by changing pH and temperature. To reduce adverse effects, starches are often mixed with stabilizers that protect them from external factors such as high temperatures or low pH.

In mayonnaise emulsions, modified starches are also used. The process of starch modification consists in structuring starch and obtaining its derivatives with different properties.

Nutritional supplements. Food additives - natural or artificial components introduced into food to give it certain properties.

Flavoring additives used in mayonnaises and sauces include sweetening, salting, acidifying and acidity regulating, flavoring, flavoring and spicy substances.

The main sweetener in mayonnaise recipes is sugar (sucrose), while dietary varieties use glucose, fructose, as well as polyhydric alcohols (sorbitol and xylitol) and other sweeteners.

Table salt in mayonnaise recipes serves to improve palatability and detecting the taste of other components. Salt also has a preservative effect.

Spices are introduced into recipes in the form of ready-made extracts, essences, which are produced by the industry, as well as in powder form. It is also possible to use essential oils obtained by extraction with volatile solvents - oleoresins.

Powdered spices are various dried parts of spicy plants, characterized by pronounced aromatic and taste properties.

The main spice present in almost all recipes is mustard. Spices such as pepper, cinnamon, cloves, ginger, cardamom, nutmeg, dill, parsley, marjoram, etc. serve to create a variety of specific taste and aroma of mayonnaises and salad dressings.

Food acids (acetic or citric) when added to mayonnaise are both flavoring and preservatives. By lowering the pH of low-calorie emulsions from 6.9 to 4.0-4.7, they prevent the growth of undesirable microorganisms. Citric acid is softer, gives mayonnaise an exquisite taste.

Preservatives in mayonnaise products play a very important role, extending the shelf life of the product. Preservatives are conditionally divided into preservatives proper and substances that have a preservative effect, in addition to other useful properties. The former directly affect microorganisms, while the latter change the conditions for their growth and reproduction (pH of the medium, etc.). In the production of mayonnaise, salts of sorbic and benzoic acids are mainly used. The amount of preservative added to mayonnaise products is determined taking into account the following rules:

The effectiveness of the preservative is higher in an acidic environment: the higher the acidity of the product, the less preservative is required;

Reduced-calorie mayonnaises with a high water content are more susceptible to bacterial spoilage, so the amount of preservative added is increased by 30-40%;

The addition of sugar, salt, vinegar and other preservatives reduces the amount of preservative required;

Used in the production of mayonnaise preservatives based on sorbic and benzoic acids are heat-resistant compounds, but can partially evaporate with steam.

functional additives. A new direction in the creation of mayonnaise products is the introduction of additives into formulations that are especially beneficial for human health. In accordance with the theory of healthy eating, the ideas of which are currently being widely introduced into practice throughout the world; food products consumed by humans should contain functional ingredients that help the human body resist the diseases of modern civilization or alleviate their course, slow down the aging process, and reduce the impact of unfavorable environmental conditions.

Some of these components are included in the formulation of mayonnaise products, others are being studied. Currently, 7 main types of functional ingredients are effectively used: dietary fiber, vitamins, minerals, polyunsaturated fats, antioxidants (which can largely be attributed to food additives), oligosaccharides, as well as a group including trace elements, bifidobacteria, etc.

In the production of food emulsions such as mayonnaise, two methods of preparation are used - cold and hot (sometimes it is called semi-hot, which is more correct from the point of view of technology). There is also a kind of semi-hot processing - the so-called coolie method.

In the cold method, all components are mixed at room temperature. Basically, this method is used for the production of high-calorie mayonnaises (with a fat content of 70-80%).

In the cold production of medium and low-calorie mayonnaise, it is necessary to strictly maintain a sufficiently low acidity of the product, observe the dosage of sugar and salt to obtain the optimal dry matter content, and additionally add a preservative to increase the shelf life of the products.

To disadvantages this method include the high acidity of the product, the presence of a preservative in the product, and the need to use only water-soluble hydrocolloids and modified starches.

In the semi-hot method of production, the main ingredients are added to water heated to 95 ° C; at the same time they are pasteurized. Then the pasteurized mass is cooled to a temperature not exceeding 65 ° C, and only after that an emulsifier and oil are added to it. This method of production eliminates the disadvantages inherent in the cold method (although it is still not recommended to sharply reduce the acidity with this method). However, in the case of using native (and sometimes modified) starches, the thickening of the mixture occurs too early and when passing through the homogenizer, the gel is destroyed, the product turns out to be liquid and unstable in storage.

To prevent this phenomenon, the coolie method is used, in which only a solution of a thickener - starch in a small amount of water is subjected to heat treatment. The finished thickener is cooled and mixed with the rest of the ingredients. The disadvantage of this method is that the formation of the emulsion takes place in an acidic environment, in the presence of salt and sugar. The process of preparation of mayonnaise emulsions can be both periodic and continuous.

The batch method for preparing mayonnaise emulsions has two important advantages: the relatively low cost of equipment, as well as the flexibility and stability of a small production.

The hot method of preparing mayonnaise provides ample opportunities for organizing continuous high-capacity production. Most often it is used in the technologies of medium and low-calorie emulsions, which require a number of preparatory operations before the main emulsification process.

The batch production process for mayonnaise includes the following steps:

1. Preparation of the components included in the recipe.

2. Preparation of mayonnaise paste. The dry ingredients are dissolved in two mixers: in one - milk powder and mustard powder, and in the other - egg powder. Water is supplied to the first mixer at a temperature of 90-100 °C, the mixture of powdered milk and mustard is kept for 20-25 minutes. at a temperature of 90-95 °C, followed by cooling to 40-45 °C. A mixture of egg powder is heated with steam to 60-65 C and kept for 20-25 minutes. for pasteurization, and then cooled to 30-40 °C (water is supplied to the second mixer at a temperature of 40-45 °C). The mixtures from the two mixers are then combined. The concentration of solids in the mayonnaise paste for high-calorie mayonnaise should be at least 37-38%, for the rest - 32-34%.

3. Preparation of a coarse mayonnaise emulsion. It is carried out in large mixers equipped with mixing devices with a low speed. Pasta is first fed into a large mixer, then vegetable oil, a solution of salt and vinegar.

4. Homogenization of the mayonnaise emulsion in piston homogenizers at a certain pressure to avoid separation of the emulsion.

The production of mayonnaise in a continuous way on an automated line using heat exchangers of the "Votator" type consists of the following operations:

1. Prescription dosing of all components in the preparatory block.

2. Mixing of components and formation of mayonnaise emulsion (15 min.).

Mayonnaise is produced in batch and continuous ways. The emulsion is prepared by cold (at room temperature) or hot (components are added to water heated to 90-100 ° C) methods.

Features of the introduction of components. To prepare high-quality mayonnaise emulsions, it is necessary to know certain features of the introduction of components. To obtain a high-quality emulsion, the emulsifier, stabilizer and thickener (if the latter are used in the recipe) must first be dissolved in water, and then oil should be added.

Unlike stabilizers and thickeners, emulsifiers (egg or dairy products) are highly soluble in water, however, it must be remembered that at temperatures above 65 ° C, egg whites denature and cannot perform a stabilizing function. Therefore, in the hot technology of mayonnaise preparation, the emulsifier is introduced into the cooled mixture of stabilizer and thickener.

Stabilizers and thickeners are poorly dispersed in water and, when dissolved, can form lumps, the top layer of which is wetted and compacted, not allowing water to enter. To avoid this phenomenon, the following technique is used: the stabilizer and thickener are first dispersed in a certain amount of oil, and the ratio of solid and liquid phases by weight is maintained as 1: 2. After that, the dispersed mixture is easily dissolved in the aqueous phase, avoiding clumping.

Oil is added to the aqueous solution of emulsifier, stabilizer and thickener ready for emulsification. To form a finely dispersed emulsion, it is recommended to add the oil either in a thin stream or in small doses. After the formation of a normal emulsion, sugar and salt are added to it, mixed, and after that (last) the remaining components are added: mustard, vinegar, flavors, dyes, preservatives in accordance with the recipes. The components are added in the specified sequence in order to preserve the quality of the resulting emulsion as much as possible: sugar and salt, as strong hydrophiles, can prevent the stabilizer from swelling; prematurely added vinegar creates an acidic environment in which hydrolysis of the stabilizer and thickener can occur.

The commodity value of a batch of grain depends not only on the market situation, that is, on the conditions of supply and demand, but also, and especially, on the quality of the grain.

Quality is judged by many characteristics, which can be grouped into two groups:

score by appearance including cleanliness, brilliance, fullness, uniformity and absence of crushed, germinated or broken grains; color and smell are also important;

assessment by analysis to determine characteristics such as hardness, germination, mealy content, vitreousness, humidity, temperature and nature.

AT international trade usually the quality indicators of a batch of grain are quite well known to the owner and are confirmed by an official certificate. If the consignment is delivered (by sea or land) to normal conditions, then it can be assumed that the grain quality indicators do not change when it is delivered to its destination. During transportation, the cargo is insured by the owner in accordance with the generally accepted insurance policy against various hazards and possible damage.

Appearance rating

Appearance rating has a large practical value and includes the following criteria.

Humidity. Excessive grain moisture is already noticeable to the touch. However, sample analysis is only reliable if the sample is placed in an air- and moisture-tight package to prevent shrinkage.

Shape and size grains also affect the value of the batch. The shape depends on the type of grain and should be as uniform as possible. Grain size is important because large grains contain fewer coats and more endosperm than small grains.

Shell state. Damaged and crushed grains reduce quality. Damage may occur during cleaning, drying, transport, storage or handling.

Uniformity. Grains of the same variety and culture usually have the same shape and size. grain mixture various shapes and sizes usually indicate mixing varieties.

impurities. Foreign matter, grains from other crops, small stones, sand, pieces of rope, chaff, burnt grains cause difficulties in subsequent cleaning and thus reduce the quality of the lot. Sometimes the origin of a batch can be determined by the type of impurities it contains.

Smell is one of the most important indicators reflecting the characteristics of the external state of the grain. A good smell is considered to be comparable to the smell of fresh straw. A stale odor often indicates that the grain has been stored for a long time in high humidity conditions. This can affect the viability and germination of the grain.

Color and shine must be uniform and consistent with those characteristic of the variety.

However, some drying methods may cause color differences. Color evaluation should also be taken into account when analyzing the origin of a lot; for example, grain grown in damp climates is usually somewhat darker than grain grown in drier climates.

Analysis score

Laboratory analysis involves the control of such properties as moisture, temperature, nature, grain size, weight of 1000 grains and germination energy, the latter being the most important quality indicator.

Humidity, along with temperature, has a very great importance for grain storage. Grain products absorb or release moisture until they reach equilibrium with the relative humidity of the environment.

This relationship between grain moisture and relative humidity or vapor pressure is usually described using a moisture sorption isotherm. This can be an absorption or desorption isotherm, depending on what initial moisture content the grain sample had - more or less than the equilibrium moisture content.

In the first case, when the initial moisture is greater than the equilibrium moisture, the sample will lose moisture in order to reach an equilibrium state (desorption). If the initial moisture content is less than the equilibrium moisture content, the sample will absorb moisture to reach the equilibrium state (absorption).

Are used various methods humidity determination. Older methods are usually complex, but give more accurate results. Modern instruments that measure grain specific permittivity (dielectric constant) are not as accurate, but they work more quickly. In most cases, modern methods give results whose accuracy is acceptable for daily practice.

Temperature. If the temperature of the grain mass is too high or rises at a constant rate, this threatens with undesirable consequences.

The temperature of the batch of grain is measured at the greatest possible depth of the grain mass and at various points. For this purpose, thermal rods are used for bulk masses, and in deep silos, the temperature is measured using sensors installed in the grain mass at various depths.

Nature is determined on standard instruments by weighing the contents of a container filled under certain controlled conditions.

It can usually be assumed that a high nature indicates great content endosperm, although other factors affect this value, such as grain shape, relative humidity, grain temperature during analysis, and impurity content.

Sieve Control. The size and uniformity of the grain is determined in triplicate using a laboratory sieve with different hole sizes. At the same time check the content of impurities. Sieve analysis is simple and allows you to quickly determine whether the batch meets the requirements.

Weight of 1000 grains. The average grain weight is determined by weighing 1000 grains. The moisture content of the grain must be taken into account, otherwise wetter grains will appear heavier than drier ones. The weight of 1000 grains varies depending on the variety, cultivation area, etc.

vitreousness determined by cutting the caryopsis on the farinotome into two parts and studying the cross section. For the same purpose, grain transparency is sometimes determined using a light source. Vitreous grains appear transparent, while mealy grains appear opaque. Usually this analysis is too complex and does not give a definitive answer to the question of the quality of the lot.

Germination analysis gives the best picture grain condition. It is necessary to distinguish between "germination", i.e., the ability of seeds to produce normal sprouts or develop under favorable, normal conditions, and "germination energy", which is characterized by the percentage of seeds germinated after a certain number of days. Malting barley, for example, should have a minimum germination energy of 95%. In addition to high germination energy, germination uniformity is important. In this case, the age of the grain must be taken into account. In practice, there are many methods for determining germination, but most of them are not widely used, as they are difficult to perform and require too much time. Usually, 100 grains are randomly selected and the number of germinated grains is counted after three days. Also check the uniformity of seedlings.

Lecon method more efficient: the grains are immersed in a solution of tetrazolium salt, from which they absorb oxygen. After a few hours the color of the grains changes and the number of viable and dead grains can be counted. For wheat, 60% indicates poor baking quality, 70% fair, while 80% indicates that the grain is generally suitable for baking.

Controlling the presence of granary weevils. Barn weevils are dark brown beetles with a proboscis, 3-5 mm long, with underdeveloped wings. They develop deep in the grain mass and are usually not visible on the surface. Barn weevils feed on grain and thus cause a significant loss of its mass, increased humidity and temperature.

Mandatory, determined in any batch of grain, are signs of freshness (color, smell, taste), contamination of grain with pests, humidity and contamination of it.

Target signs are determined in batches of grain of individual crops used for specific purposes. These include filminess (rice, buckwheat, millet), vitreousness (wheat, rice), the quantity and quality of raw gluten, nature (wheat, rye, barley and oats), viability, content of small and damaged by a turtle bug, frost grains.

Additional signs are the chemical composition of the grain, the content of microorganisms, etc.

Grain freshness is determined external inspection his sample. By color, luster, smell, taste, they judge the good quality of the grain or the nature of the defects present in the test batch. Fresh benign grain has its own color and luster. Therefore, the color of the grain underlies the commodity classifications adopted in the standards.

A grain with a changed color differs from the normal one in terms of chemical composition and structure. Such grain is referred to as a grain, and sometimes as a weed impurity.

Smell grains are weak, barely noticeable. A sharp change in this indicator indicates damage to the grain (mold, self-heating, rotting) or sorption of odorous substances by the grain (the smell of weeds, smut, oil products, smoke). The presence of odor in the grain degrades its quality.

The smell is determined in whole or ground grain. To enhance the sensation, its grain is heated in a flask at a temperature of 40 ° C.

Taste normal grain is very weakly expressed. Taste deviations are determined organoleptically. sweet taste manifests itself during germination, bitter - from the ingress of wormwood, sour taste - with the development of mold on the grain.

Humidity is one of the most important indicators of grain quality. It affects the nutritional value of grain, its safety, and the processing process. Humidity is taken into account when receiving grain, when laying it for storage, and when it is released from storage. The standards provide for four states of grain moisture: dry, medium dry, wet and wet. Grain wet and raw is suitable for storage without drying.

All components of the grain mass are divided into groups: the main grain, which is a raw material for processing, and impurities (components not used for processing). Only certain impurities in strictly defined quantities are allowed in batches of processed grain. The main grain includes full and damaged grains of this crop.

impurities are divided into two groups: weed and grain.

Weed impurity negatively affects grain quality. Its composition is heterogeneous. It includes mineral, organic impurities, seeds of cultivated and wild plants, grains with a clearly damaged kernel or eaten by pests.

A special fraction is a harmful impurity: ergot, smut, eel, seeds of poisonous weeds, cockle. The content of weed impurities and its individual parts (harmful, mineral, spoiled grains) is normalized by standards. Weed impurities are taken into account in cash settlements for grain, as well as grain with non-standard moisture content to determine the test weight of a grain batch.

Grain admixture affects the quality of a batch of grain and its stability during storage. Therefore, its content is normalized when selling grain to the state, during processing. Grain admixture affects the quality of grain to a lesser extent than weed. When grain is sold to the state, only a small discount is made from the price for grain admixture in excess of the established norm.

Pest infestation is determined in any batch of grain during acceptance, shipment and storage. Pests destroy part of the grain, reduce its quality, pollute with the products of their vital activity, give an unpleasant taste and smell. Pests accumulate heat in the grain, which can cause self-heating and damage to it. Weevils, beetles, butterflies, and mites cause the greatest harm to grain stocks (Fig. 12). A batch of grain is considered infected if live pests are found at any stage of development. During grain storage, insects and mites can develop.

The infestation of a grain sample is determined by sifting it through a sieve, then live pests are counted. Infection is expressed by the number of live pests per 1 kg of grain. For common pests, the standard established the degree of infestation (Table 14).

Grain receiving enterprises and procurement offices do not accept grain infected with pests. A batch of grain infected with a tick of the 1st degree is accepted at a discount from the price.

Grain nature- the mass of 1 liter of grain, expressed in grams. Nature is determined using a liter purka. Its value is influenced various factors(degree of completion, fineness, chemical composition, contamination, humidity). When selling grain to the state, this indicator is used for cash settlements.

Filminess- the percentage of films in the grain (for buckwheat fruit shells). According to the content of the films, it is possible to calculate the yield of cereals.

vitreousness- consistency of grain endosperm on a cross section; determined by examining grain sections on a diaphanoscope. The grain is divided into vitreous, farinaceous and partially vitreous.

Rice. 12. Pests of grain and products of its processing: 1 - weevil; 2 - pretending thief: a - beetle, b - larva; 3 - small flour beetle: a - beetle, b - larva; 4 - flour mite; 5-mill moth: a, b - butterflies, c - caterpillar

Table 14. The degree of infection of grain with granary pests

Gluten- a water-insoluble protein clot remaining after washing the dough from water-soluble substances, starch and fiber. The gluten washed out from the dough is called raw. The bulk of gluten proteins are glutelin and gliadin. After washing in water, the mass of gluten is determined, its quality: color, elasticity, extensibility. Depending on elasticity and extensibility, gluten is divided into three groups.

The more gluten in the grain and the better its quality, the higher the technological advantages of the grain. In grain damaged by the turtle bug, frost, drying, sprouted gluten is dark, short-tearing or crumbling.

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 a particular batch or variety.

The test results depend on three components:

• genetic features the crop from which the crop was harvested;
• growing conditions and transportation technology;
• storage.

The approved state quality assessment unit 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 characterizing the degree of usefulness and suitability of grain for technical and agricultural use;
• safety indicators - assess the presence of harmful chemical impurities, characterize the environmental friendliness of grain;
• the content of GMOs (genetically modified samples).

The first group is the most extensive and is an obligatory component of checking grain lots. The quality assessment includes 2 types of grain analysis indicators:

• organoleptic - evaluated with the help of human senses;
• laboratory or physico-chemical - are determined using specific methods and technical equipment.

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

Deciphering grain analysis

Parameter	Characteristic
Humidity	Percentage of water content in 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	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 weight of 1000 grains, specific gravity, as well as the length, width and thickness of the seed.
vitreousness	Characterizes the degree of transparency of the grains.
Filminess	Determined for cereal crops (oats, barley, rice, buckwheat, etc.). Characterizes the percentage of films or shells in the grain mass. The higher the filminess, the lower the yield of finished cereals.
Infestation	Shows the percentage of impurities to the total mass of grain.
Germination	The ability to produce normal sprouts in natural conditions for a particular culture.
Germination energy	Percentage of grains that sprouted within a specified period of time.
Fall 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 the complete combustion of ground grain at a temperature of 750-850 ° C.
evenness	Characterizes the uniformity of grains in size.
Infection	The number of pests in the crop (turtle bugs, etc.) is expressed as the number of live individuals per 1 kg of grain.

For wheat, the 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 scientific research crops that accompany the development of new varieties or the study of the influence of various environmental factors on cereal plants (fertilizers, soil, pests, phytohormones, etc.).

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

seed grain

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

• sample 1 - purity, germination, weight of 1000 seeds;
• sample 2 - humidity and pest infestation;
• sample 3 - the degree of damage to seeds by diseases.

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

Germination is determined by placing 100 seeds in suitable conditions for germination for 3 days. At the same time, the number and uniformity of seedlings are evaluated. For the rapid detection of dead grains, the Lecon method is effective, which gives results in a few hours. Live grains are identified by the color change that occurs when oxygen is absorbed from a tetrazolium salt solution. In dead seeds, there is no respiration.

Organoleptic evaluation

The main organoleptic indicators are color, gloss, 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 foreign odors (not characteristic of the culture) indicates deterioration or violation of storage technology.

The following are also assessed by eye:

• shape and size;
• batch homogeneity;
• weediness;
• shell state.

The color, smell and taste of the grains are checked for compliance with a specific biological variety. Organoleptic analysis is superficial and approximate, but may reveal serious deviations from the norm. 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 divided 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 poisonous to humans.

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

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

Infection can be overt and covert. In the first case, pests are separated from the sample using a sieve, and in the second case, each grain is split and examined (sample size is 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 technical usefulness. For example, a large amount of lipids in sunflower seeds indicates the high suitability of raw materials for oil production.

The definition of some components of the composition is a key fatcore of quality. 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 vitreousness and quality of the gluten.

Equipment

There is a huge number of instruments for grain analysis, among which are specialized (designed for laboratory evaluation of grain products) and general. The latter include instruments for physical and chemical measurements, equipment for working with reagents.

The standard laboratory kit for grain analysis includes:

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

The kit may also contain narrow-profile devices, for example, peelers, with the help of which 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 established using a diaphanoscope. Automation of grain analysis significantly reduces the subjective factor and saves time.

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

At present, 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 technical support a specific laboratory and a set of indicators to be checked.

Determination of humidity

Humidity 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 (ESH) - consists in drying the ground grain sample and comparing the weight before and after the procedure;
• using an electric moisture meter - determining the degree of moisture by electrical conductivity, a grain sample is placed in the device under the press.

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

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

• 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.).

Humidity more than 14% is considered high and undesirable, as 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

Filminess assessment includes 2 stages:

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

The second indicator is the most important. To determine it, the grains are first freed from the shells using a peeler or manually, and then the cereals and the film mass are weighed separately. At the end, the weights of the cleaned and uncleaned samples are compared.

vitreousness

The degree of transparency depends on the ratio of protein and starch. The higher the content of the latter, the more powdery (starchy) and cloudy the grain. Conversely, a large amount of protein increases the transparency of the seed. Therefore, the glassiness 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 vitreousness, the stronger the grain and the more energy costs for grinding.

There are 2 methods for determining this parameter: manual and automated. In the first case, transparency is assessed by eye or using a diaphanoscope. A sample of 100 grains is subjected to analysis. Each seed is cut in half and assigned to 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 number of partially vitreous seeds is 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 grains.

Fall number

The 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 into simple sugars, which are necessary for the development of the seed embryo. Naturally, this leads to a significant decrease in baking quality.

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

GOSTs of grain analysis

All components of product analysis are strictly regulated and prescribed in the relevant standards. GOST contains quality standards, equipment requirements and methods for determining each indicator. The results of the analysis of grain are recognized as reliable only if they are obtained in accordance with established instructions.

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

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

Express analysis of grain 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%.

The work of complex analyzers is based on the diffuse reflection of light with a wavelength within the near infrared region. At the same time, time is significantly saved (analysis of several parameters is carried out within a minute). The main disadvantage of the express method is the high cost of equipment.

Gluten content and quality analysis

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 (from 80 to 90% of dry matter);
• complex carbohydrates (starch and fiber);
• simple carbohydrates;
• lipids;
• minerals.

Wheat contains from 7 to 50% raw gluten. Values ​​greater than 28% are considered high.

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

• elasticity;
• extensibility;
• elasticity;
• viscosity.

The most important indicator is elasticity, which characterizes the baking properties of wheat. To determine this parameter, a gluten deformation index (DIC) instrument is used. The sample for analysis is a ball rolled up from 4 grams of the test substance and previously soaked 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 is to wash the analyte from the dough, mixed from wheat meal (crushed and sifted grains). Laundering is carried out under a weak water jet at a temperature of +16-20 °C.