The market value of a batch of grain depends not only on the market situation, i.e., 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 combined into two groups:
evaluation for appearance, including cleanliness, gloss, fulfillment, uniformity and absence of crushed, sprouted or broken kernels; color and smell are also important;
evaluation by analysis to determine characteristics such as hardness, germination, mealy content, vitreousness, moisture, temperature and nature.
In international trade, the quality indicators of a batch of grain are usually well known to the owner and confirmed by an official certificate. If the batch is shipped (by sea or land) under normal conditions, then it can be assumed that the quality indicators of the grain 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 in the event of various hazards and possible damage.
Appraisal by appearance
Evaluation by appearance is of great practical importance and includes the following criteria.
Humidity... Excess grain moisture is already noticeable to the touch. However, the analysis of the sample is only valid if the sample is placed in an air- and moisture-tight container 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 the same as possible. Grain size is important because large grains contain fewer shells and more endosperm than small grains.
Shell state... Damaged and crushed kernels reduce the quality. Damage can occur during cleaning, drying, transportation, storage or handling.
Uniformity... Grains of the same variety and crop usually have the same shape and size. A mixture of grains of different shapes and sizes usually indicates a mixture of varieties.
Impurities... Foreign matter, grains of other crops, small stones, sand, pieces of rope, chaff, burnt grains cause difficulties during subsequent cleaning and thus reduce the quality of the batch. 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 that of fresh straw. A stale smell often indicates that the grain has been stored for a long time in high humidity conditions. This can affect the vitality and germination of the grain.
Color and shine must be uniform and consistent with those characteristic of the class.
However, some drying methods may cause color differences. Color assessment should also be considered when analyzing the origin of the lot; for example, grain grown in damp climates is usually slightly darker than grain grown in drier climates.
Assessment by analysis
Laboratory analysis involves monitoring properties such as moisture, temperature, nature, grain size, 1000 grain weight and germination energy, the latter being the most important quality indicator.
Humidity, along with temperature, is very important for grain storage. Cereals absorb or release moisture until they are in equilibrium with the relative humidity of the environment.
This relationship between grain moisture and relative humidity or vapor pressure is usually described using the moisture sorption isotherm. This can be an isotherm of absorption or desorption, 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 content is higher than the equilibrium moisture content, the sample will lose moisture in order to reach equilibrium (desorption). In the event that the initial moisture content is less than the equilibrium moisture content, the sample will absorb moisture to achieve an equilibrium state (absorption).
Various methods are used to determine moisture content. The older methods are usually complex but give more accurate results. Modern devices that measure the specific dielectric constant of a grain (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 a 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 different depths.
Nature is determined on standard instruments by weighing the contents of a container filled under specified controlled conditions.
Usually, it can be assumed that a high nature indicates a high content of endosperm, although other factors affect this indicator, for example, grain shape, relative humidity, grain temperature at analysis and the content of impurities.
Sieve control... The grain size and uniformity are determined in triplicate using a laboratory sieve with various hole sizes. At the same time, the content of impurities is checked. Sieve analysis is straightforward and allows you to quickly determine if a batch meets your 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 mass of 1000 grains varies depending on the variety, cultivation area, etc.
Vitreousness determined by cutting the caryopsis into two parts on the farinotome and examining the cross-section. For the same purpose, the transparency of the grain is sometimes determined using a light source. Glassy 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 batch.
Germination analysis gives the best picture of the state of the grain. It is necessary to distinguish between "germination", that is, the ability of seeds to sprout 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, since they are difficult to perform and take too much time. Typically, 100 grains are randomly selected and the number of germinated grains is counted after three days. Also check the uniformity of seedlings.
Lecon's method more effective: the grains are immersed in a solution of tetrazolium salt, from which they absorb oxygen. After several 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% is fair, while 80% indicates that the grain is generally suitable for baking.
Monitoring 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 significant weight loss, increased humidity and temperature.
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The need of the Russian Federation for high-quality wheat of the 3rd class for the production of bakery flour - about 19 million tons - this is the 3-4th part of the wheat harvest. However, there are often only 40-50% of such grain. Getting high quality food grain remains a problem for all grain-growing regions of the country.
In the Kurgan region, wheat is grown on an area of 890-900 thousand hectares, occupying up to 66% of crops. Previously, the share of the third class was 91-96% of the surveyed lots of wheat, in recent years it has dropped to 11-12%. What is the reason for the failure? Let's try to figure it out. The journal will publish several articles on this issue. In this material, indicators of wheat quality are discussed.
Grain quality is determined by a number of parameters, including technological and baking indicators that characterize the consumer properties of wheat: natural weight, glassiness, gluten content, falling number, flour strength, bread volume, bakery rating and others.
Natural weight depends on the size and density of the grain, the state of its surface, the degree of filling, the mass fraction of moisture in the grain. The basic and limiting norms of the full-scale weight have been established - 750 and 710 g / l. To achieve these levels, the degree of favorable weather conditions during the loading and ripening phases is very important. Fertilizers and good moisture supply of the growing season had a positive effect on this indicator in the experiments of the Kurgan Research Institute of Agriculture. The natural weight is closely related to the grain size - 1000 grain weight. Large grain of wheat weighs more than 35 g, small grain - less than 25 g.
Vitreousness wheat is a sign of grain hardness, as well as an indirect indicator of the presence of protein substances, is associated with the consistency of the grain, loose or dense placement of protein fragments among carbohydrates. The indicator fluctuates due to varietal characteristics, climatic factor and weather of individual years. A decrease in vitreousness occurs with abundant precipitation of ripe, but not yet harvested wheat, often accompanied by grain dehydration and a decrease in its marketability. The use of nitrogen and nitrogen-phosphorus fertilizers has a positive effect on vitreousness.
In addition to technologically significant indicators (according to the level of vitreousness, the grain is locked before grinding), it characterizes the commercial grain of wheat by its nutritional value. Important in the composition of wheat grain is the amount protein or protein(there is very little non-protein nitrogen in the grain). Its content 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 two gluten proteins is formed in wheat. At the same time, there is a decrease in baking qualities. In most countries, the protein content is determined in grain, it depends to a greater extent on the level of the emerging crop, especially on poor nitrogen backgrounds, where there is an inverse relationship between the yield and the protein content of wheat. With fertilization, both indicators increase, and this relationship weakens. Protein content in grain is calculated as the percentage of total nitrogen in grain using a factor of 5.7.
In addition to the indicators standardized by GOST P52189-03, the dignity of flour is assessed by a direct method for assessing its baking properties - a test laboratory baking of bread with an assessment of its quality in terms of volume yield, dimensional stability, appearance, crumb condition, porosity and other indicators. To obtain fluffy and uniformly porous bread, the gas-generating and gas-holding capacity of the dough must be balanced. The properties of the test are assessed using a farinograph and an alveograph. According to the width and area of the farinogram, the valeometric estimate is calculated. The higher this value, the better the test score. In baking, a lot is also decided by the value of the water absorption capacity of protein, due to which the swelling of flour during the preparation of the dough will differ significantly.
The ability to form a dough with certain rheological properties: elasticity, elasticity, plasticity, viscosity and the degree of liquefaction characterizes the power of flour. The patterns of changes in the strength of flour and the volumetric yield of bread over the years are similar: in warm dry years, the values are much higher than in wet ones.
However, the analyzes for bakery evaluation are quite lengthy and complex. Therefore, when trading operations with grain, they use faster identifiable characteristics. First of all, it is the quantity and quality of gluten, which characterize the strength of wheat and its properties as an improver.
Amount of gluten is characterized by the content of gluten proteins in the grain (glutenins and gliadins), which make up about 80% of all proteins of wheat flour and are mostly concentrated in the endosperm of the grain. The indicator can fluctuate within a very wide range from 18 to 40% or more. The presence and properties of gluten determine the gas-holding capacity of the dough and determine the structure of the baked bread. The gluten content in soft wheat grain of 36% and more corresponds to the highest class of food grain; 32% - 1st class; 28% - 2nd; 23% - 3rd; below 23 to 18% - 4th grade, less than 18% - 5th.
Great importance is attached gluten quality, which is mainly a varietal trait. It includes: extensibility, elasticity, elasticity, viscosity, the ability to maintain the original physical properties in the process of washing. The elastic properties of gluten are determined by a strain gauge (IDK). For the highest, 1st and 2nd grades, the 1st group of gluten quality is required with indications of 45-70 IDK units. For the 3rd and 4th grades, the 2nd group is allowed - satisfactorily weak (80-100 units) or satisfactorily strong (20-40 units). Readings of more than 100 and less than 20 units are considered unsatisfactory.
If the amount of gluten can be purposefully changed by improving the nutritional conditions of wheat, selection of varieties and sowing dates, then its quality is a less regulated indicator. The quality of gluten is influenced by the conditions for growing wheat, the degree of maturity of the grain, damage by frost, bug-turtles, etc.
The quality of gluten also depends on the temperature and moisture conditions in the phases of milky-wax and waxy ripeness of the grain. According to the observations of Kazan scientists, group 1 is formed more often when the air temperature is 20-22˚С during the period of grain formation. Observations of the Kurgan grain inspection on a large number of wheat consignments showed that the 1st group was noted in sufficient volume in warm years. According to the data of the grain inspection, this indicator has changed so much over the years. There was no group 1 during the prolonged drought and heat of 1989, as well as in the dry 1994 and humid 1990s. In 1995-1997 the share of such grain was only 7-14%, in 1998 and 1999. 30-34%. The share of the 1st group of gluten quality in the warm year of 2000 was significantly higher - 69%.
According to the data of the variety network for 12 years (1987-1998), in 50% of years the IDC was in the range of 40-75 units. Most often, these values referred to samples of early and middle sowing dates from the southeast of the region. The first group was characterized by the previously widespread varieties Zhigulevskaya, Saratovskaya 39, Kurgan 1, Omskaya 18 and Tulaykovskaya.
For a long time, they tried to explain the different properties of gluten in weak and strong wheat by the amino acid composition, but it turned out that it was close. Comparison of gluten fractions by amino acid composition was the same, except that strong wheat has almost 2 times more cystine and cysteine residues than weak wheat. Then it was believed that the reason was the different ratio of fractions - gliadin and glutenin.
The properties of gluten are influenced by the spatial structure of the protein. Studies by Vakar and Kolpakova are of great interest, according to which the fractions of strong gluten are built more compactly than weak ones. Protein components are packed more densely, which is due to the large number of disulfide, hydrogen and other, mainly non-covalent bonds. Therefore, strong wheat gliadin contains more disulfide bonds. The division of gliadin into fractions in strong and weak wheat showed that high-molecular components predominate in strong gluten, and low-molecular components in weak ones. The glutenin of weak wheat mainly contains hydrogen bonds, while in strong wheat, in addition to them, hydrophobic interactions are also of great importance.
The quality of wheat grain also depends on the state of the carbohydrate-amylase complex of the grain, which characterizes the falling number, which makes it possible to judge the possibility of germination of grains in the ear, while falling number decreases sharply. The enzyme alpha-amylase in certain quantities is necessary and useful during the fermentation of dough, converting part of the starch into dextrins, and then into sugars - maltose and glucose. However, in wet autumn, when the growing crops are over-grown, the wheat grain swells and the processes characteristic of its germination begin. The enzyme alpha-amylase is activated, causing the hydrolysis of starch to dextrins and sugars. Dextrins have a low water absorption capacity, which causes a sticky crumb of bread, the crust is sluggish, the color of the crumb is gray, damp to the touch, has a malt smell.
Prolonged rains in autumn can be the reason for a sharp decrease in the falling number, which is determined by the speed of falling of the mixer plunger through the water-flour mixture, which swells differently depending on the quality of the flour. For wheat flour, the falling number is considered optimal in the range of 200-250 s (seconds), low rates of 150 s or less. Readings longer than 300 s are also undesirable. Values less than 150 s indicate poor flour swelling; above 400 s - about the opposite lack - very low activity - of amylase. In the latter case, the addition of amylolytic enzymes to the flour is recommended. In Kurgan oblast, in most of the years under study, the number of falls in the examined lots of wheat was in the optimal range, except for years with cold, wet autumn.
Further in the journal there will be a series of articles on ways to improve the quality of wheat. I would like the production specialists to share their experience of growing valuable wheat.
Introduction. Safety in the laboratory. Laboratory equipment
2 Weighing
3 Determination of moisture
5 Infection of grain with pests of grain stocks
6 Determination of the nature of grain
7 Determination of ash content in grain
8 Determination of glassiness of grain
10 Determination of the baking properties of flour
11 The latest laboratory equipment. Grain-receiving and grain processing enterprise
2 Elevator operation
4 Warehouses and grain products
6 The process of operating a grain dryer. Technochemical analysis of grain
1. Weight analysis
2 Sampling
3 Indicators of freshness of grain
4 Grain moisture
5 Indicators of grain contamination
7 Pests of grain stocks
8 Mineral substances of grain
9 Acidity
10 Physical properties of grain mass
11 Analysis of grain of cereals and buckwheat
14 Analysis of seed (sowing) grain. Technological analysis of grain processing products
1 Sampling and analysis of flour
2 Sampling and analysis of cereals
Conclusion
Introduction
In the period from 31.10.13. until 4.12.13. passed practice on the basis of LLP "Argimer Astyk", from 15.05.14. until 4.06.14 an internship was carried out on the basis of the SMMO College of Agribusiness.
The purpose of this practice is to acquire skills in working with equipment at the enterprise.
According to the set goal, the following tasks were completed:
familiarize yourself with the safety precautions at the enterprise;
study the structure of the elevator and laboratory;
take a sample correctly;
clean grain from various impurities;
learn to sort the grain;
allocate an average grain sample;
learn how to use the equipment correctly;
conduct analyzes for moisture, contamination, etc.
The elevator is a complex industrial production. To manage such an enterprise, it is necessary to understand many issues related to the proper storage of both grain and oilseeds, to know the technology of all production, techniques and methods of effective use of grain and equipment. The development of systems of technological processes and machines for the processing industry of the agro-industrial complex is one of the most important tasks of scientific organizations in our country.
Based on modern requirements, many operating elevators need deep reconstruction or technical re-equipment based on a new generation of equipment and automation equipment. Domestic standard technological processes occurring at the elevator are still lagging behind foreign counterparts in terms of material consumption, specific energy consumption, occupied area and level of automation.
I. Briefing on safety in the laboratory. Study of laboratory equipment
1.It is necessary to work in the laboratory in a dressing gown, protecting clothing and skin from ingress and corrosive reagents and contamination by microorganisms.
2.Everyone must work at their assigned workplace. Moving to another place without the permission of the teacher is not allowed.
.The workplace should be kept clean, not cluttered with utensils and side items.
.Students are prohibited from working in the laboratory without the presence of a teacher or laboratory assistant, as well as at an unspecified time without the teacher's permission.
.Before each laboratory work, you can start only after receiving a safety briefing and permission from the teacher.
.Getting started, it is necessary: to understand the method of work, the rules for its safe implementation; check the conformity of the taken substances with those substances that are indicated in the method of work.
.The experiment must be carried out in strict accordance with its description in the methodological instructions, especially adhere to the sequence of adding reagents.
.To carry out the experiment, use only clean, dry laboratory glassware; to measure each reagent, you need to have a volumetric container (pipettes, burettes, beaker, graduated cylinder or beaker); Do not pour excess reagent poured into the test tube back into the container so as not to spoil the reagent.
.If in the course of the experiment heating the reaction mixture is required, it is necessary to follow the prescribed methodological instructions for the heating method: on a water bath, on an electric stove or on a gas burner, etc. It is dangerous to heat highly volatile combustible substances over an open fire.
.Chemical substances spilled on the floor and table are neutralized and removed under the guidance of a laboratory assistant (teacher) in accordance with the rules.
.When working in the laboratory, the following requirements should be observed: work must be done carefully, conscientiously, carefully, economically, be observant, rationally and correctly use the time allotted for work.
.At the end of the work, you should put your workplace in order: wash the dishes, wipe the surface of the working laboratory table, close the water taps, turn off the electrical appliances.
1 Sampling and allocation of portions
Grain is accepted in batches. GOST-13586 Rules for acceptance and sampling. A batch is understood as any quantity of grain, uniform in quality, intended for simultaneous acceptance, shipment or simultaneous storage, drawn up in one quality document. The quality document for each batch of harvested and supplied grain indicates:
date of execution of the document;
name of the sender and station (pier) of departure;
car, wagon number or name of the vessel;
invoice number;
lot weight or number of seats;
destination station (pier);
the name of the recipient;
the name of the culture;
origin;
grade, type, subtype of grain;
grain class;
The results of analyzes according to quality indicators provided for by the standard of technical specifications for the relevant crop; signature of the person responsible for issuing the grain quality document.
For a batch of harvested grain, shipped by a collective farm, a state farm, it is allowed to issue an accompanying document instead of a quality document, which indicates: the name of the sending farm; name of culture, variety; harvest year; car number; the mass of the party; date of execution of the document; signature of the person responsible for issuing the accompanying document.
It is allowed to issue one document on the quality or one varietal certificate for several homogeneous lots of grain, handed over during the day by one farm, by the farm.
Several consignments of grain of the same quality, received from one collective farm, state farm or a remote point during operational days, are accepted as one consignment. When grain is shipped by rail, it is allowed to issue one quality document for homogeneous lots shipped in several wagons to the address of one recipient. In these cases, the numbers of all wagons are indicated in the quality document.
To check the conformity of grain quality to the requirements of regulatory and technical documentation, an average sample weighing (2.0 ± 0.1) kg, isolated from the combined or daily average sample, is analyzed. The results of the analysis of the average sample are extended to the entire batch of grain. When grain is received from collective farms, state farms or deep points of automobile consignments of grain, the results of the analysis of the average sample isolated from the average daily sample are extended to all automobile consignments of grain of the same quality that were received from one farm within one operational day. Upon receipt of grain consignments by water transport, prior to unloading ships in the port, a preliminary examination of the grain is carried out to determine the quality by organoleptic indicators, as well as pest infestation of grain stocks.
Figure 1: Probe
Application
Turn the knob
Submerge the sampler to the desired depth.
Open the chamber, the weight moves into the chamber.
Close the camera.
Remove the sampler.
Close the sampling site with a close-it control sticker.
Simple emptying of the sample through the open end of the sample tube.
2 Weighing
Car scales are used both for weighing cars in a static scale. Electronic scales CAS are designed for measuring both cereals and oilseeds. Scales - designed to measure the mass of substances.
Laboratory scales of the CAS-type, in accordance with GOST-24104-2001, are classified as high-class scales. Reading accuracy 0.05-0.5. The balance must be plugged into the throwing outlet for at least 30 minutes before the start of operations, and for weighing in motion. Car scales for weighing in a static state are designed to determine the weight of cars with decoupling or in a train. Scales wagon for weighing in dynamics (in motion), depending on the modification, can be designed for axle-based and trolley weighing.
Figure 2: Electronic scales CAS
Electronic wagon scales for weighing in motion VZhD-D and lining wagon scales VZh-DR for wagon weighing in motion and for static weighing of 4, 6, 8-axle wagons, trolleys, tanks.
Figure 3: Wagon Scale
Truck scales of foundation and baseless design, for weighing in statics or in motion. The weighing range is from 20 to 200 tons, which makes it possible to produce any kind of cargo vehicle. The electronic components of the scales are capable of operating at temperatures from -30 to 40 (-50 to +50 special version) ° С. The scales used for the shipment of grain and products by rail are attributed to the railroad. They must be in a permanent location.
3 Determination of moisture
When determining the moisture content of wheat grain, one begins with sampling in accordance with GOST 13586.3, preparation of equipment and materials. Next, a sample weighing 300 g is isolated from the average sample. The selected grain is placed in a tightly closed vessel, filling it by two-thirds of its volume. Grain, which has a temperature below the temperature of normal laboratory conditions (20 ± 5 ° C), is kept in a closed vessel up to ambient temperature. Place a calcined calcium chloride or other desiccant at the bottom of a thoroughly washed and dried desiccator. The sanded edges of the desiccator are lubricated with a thin layer of petroleum jelly. New bottles are dried in an oven for one hour and placed in a desiccator for complete cooling. Handling bags should also be stored in a desiccator. In the selected grain, moisture is determined using an electric moisture meter in accordance with GOST 8.434 to select a method option and establish the drying duration. For grain with a moisture content of up to 17%, the determination is carried out without preliminary drying. For grain with a moisture content of more than 17%, the determination is carried out with preliminary drying to a residual moisture content in the range of 9-17%. At a temperature of 105 ° C from 7 to 30 minutes.
The moisture content of the grain is determined in two ways: with preliminary drying and without preliminary drying.
Before testing, the grain is thoroughly mixed by shaking the vessel in different directions and planes. In a dried and weighed mesh container from the prepared grain to determine the moisture content, a sample of grain weighing 20 g is taken from different places with a scoop. The container is closed and weighed. Before drying the grain, the drying cabinet is preheated to a temperature of 110 ° C and dried at 105 ° C, for which the movable contact of the thermometer is set at 105 ° C.
Figure 4: Electronic moisture meter
4 Determination of the huskiness of cereals
Based on the analysis of the appearance of the grains, characteristic morphological signs of wheat, rye and barley grain are revealed: size, color, elongation, skin, groove. At the same time, a comparative analysis is given: the size and elongation of the grain - small, medium or significant. The procedure for determining the mass of 1000 grains is carried out in accordance with GOST 10842-89 Grains of cereals and legumes and oilseeds. Method for determining the mass of 1000 grains or 1000 seeds.
Two weighed portions are isolated from the average grain sample, the mass of each of which is close to the mass of 500 grains, and weighed on a laboratory balance with an accuracy of the second decimal place (weight of the portion: rye - 15g, oats - 20g, wheat - 25g). whole grains, and the remainder is weighed to the second decimal place.
Determine the weight of whole grains by subtracting the weight of the residue from the weight of the sample. Whole grains selected from the sample are counted. Each determination is carried out on two parallel weights.
Weight 1000 grains , r, is calculated by the formula
where - mass of whole grains, g;
The number of whole grains in the mass, pcs.
The arithmetic mean of the two results of determining the mass of 1000 grains is taken as the final result, if the discrepancy between them does not exceed 10%.
Determination of the hulliness of oat grain:
Determination of the hulliness of oat grain is carried out in accordance with GOST 10843-76 Grain. Method for determination of filminess.
To determine the hulliness, it is necessary to weigh 5 g of oat grain, peel it from the film and weigh it. The index of filthiness is expressed as a percentage in relation to the weight of the sample taken. For this, the weight of the films obtained after weighing is multiplied by 20. The calculation results are compared with the data of GOST 10843 on the hulliness of oat grains.
5 Determination of grain infestation by pests of grain stocks
Grain infestation by barn pests is an important indicator of the state of the grain mass. Determination of grain infestation by insects and mites in an explicit form. Sampling and sampling is carried out in accordance with GOST 13586.3-83. Selected samples are placed in a tightly closed container, excluding the movement of insects and ticks. In case of layer-by-layer sampling, the analysis is carried out using an average sample taken separately from each layer, and the infestation is established by the sample in which the largest number of pests was found. Lumps of grain, braided by butterfly caterpillars, are taken apart by hands. The detected pests are added to the total number of pests in the average sample. After disassembling the lumps, the average grain sample is weighed and then sieved through a set of sieves with holes of 1.5-2.5 mm in diameter by hand for 2 minutes at about 120 circular movements per minute or mechanically in accordance with the description attached to the device.
If the grain temperature is below 5 ° C, the resulting descent and passages through the sieve are warmed at a temperature of 25-30 ° C for 10-20 minutes in order to activate the insects that have fallen into torpor. The exit from the sieve with holes with a diameter of 2.5 mm is placed on a white glass of the analysis board, and the passage through a sieve with holes with a diameter of 1.5 mm is placed on black glass, scattering them in a thin thin layer; the passage through a sieve with openings of 1.5 mm is viewed under a magnifying glass. At the same time, smaller pests are emitted: barn and rice weevils, grain grinder, mace and small flour beetles, Surinamese and short-mouthed flour eaters, flour and elongated mites and others. Dead pests, as well as live field pests that do not damage the grain during storage, are classified as trash and are not taken into account when determining the infestation. The resulting number of live pests is calculated per 1 kg of grain.
Degree of infestation Number of pests per 1 kg of grain Weevils Mites 1 From 1 to 5 inclusive From 1 to 20 incl. 2 6 - 10 Over 20, but move freely and do not form clusters 3 Over 10 Ticks form felt clusters Determination of grain infestation by pests in a latent form is carried out by cracking the grains or by staining "corks" (closed holes after laying eggs). Infestation by splitting grains is determined by a sample weighing 50 g, isolated from an average sample. From the sample, randomly select 50 whole grains and split them with the tip of a scalpel along the groove. The split grains are examined under a magnifying glass and live insects at different stages of development are counted. Contamination by staining "corks" is determined by a sample weighing about 50 g, isolated from the average sample. From the sample, randomly select 250 whole grains and put them in a mesh for 1 min in a cup with water having a temperature of about 30 ° C. The grain begins to swell, and at the same time the size of the "corks" increases. Then the mesh with the grain is transferred for 20 - 30 s into a 1% freshly prepared solution of potassium permanganate (10 g of KMnO2 per liter of water). In this case, not only the "corks" are painted in a dark color, but also the surface of the grains in the damaged areas. Excess paint from the grain surface is removed by immersing the mesh with grain in cold water.
Staying the colored grain in water for 20-30 s returns it to its normal color while maintaining a dark convex "cork" in the infected grains. The grains removed from the water are quickly scanned on filter paper.
The counting of infected grains is started immediately, without allowing the grains to dry out, otherwise the color of the "corks" will disappear. Infected grains are characterized by round convex spots about 0.5 mm in size, uniformly dark-colored "corks", which were left by the female weevil after laying the eggs. Grains are not classified as infected: with round spots, with intensely colored edges and a light middle, which are feeding places for weevils; with spots of irregular shape in places of mechanical damage to the grain. The infected grains are cut and the number of live larvae, pupae or weevils is counted.
Figure 5: Pests of grain stocks
6 Determination of the nature of grain
Purka consists of the following main units: pencil case, measure, filler, filling cylinder, falling weight, knife. To work with purka, electronic scales up to 3kg of the 4th class are required. The pencil case serves as the basis for assembling the purge for work. The measure is a cylindrical glass with a hole in the center of the bottom. There is a slit for a knife at the top of the measure. The measure is installed in the flange of the box. The filler is made in the form of a hollow cylinder with grooves at the ends. This allows the filler to fit snugly onto the measure. The filling cylinder is installed on the filler. The fill cylinder has a cut-out window at one end. Here, a funnel with a flap and a lock is mounted inside the cylinder. The falling weight is made in the form of a cylinder with an annular groove. The knife is made of sheet, has a cutout in the form of a right angle. If the falling weight is at the bottom of the gauge, then the volume of the gauge between the upper plane of the knife is equal to one liter.
Purka is designed to determine the nature of the mass of grain in one liter and are used in the laboratories of elevators, bakery factories and mills. Pfeuffer offers 1 liter of purée. Scales can be supplied in addition to the purka.
1.7 Determination of the ash content of grain
Ash content is an important metric used to assess the quality of flour. The higher the ash content of the grain, the lower the yield of high-grade flour. Ash content characterizes the amount of ash (mainly oxides of phosphorus, potassium and magnesium) obtained by burning grain at t = 750-850 ° C, expressed as a percentage.
The ash content is different in individual parts of the wheat caryopsis. Thus, the maximum ash content is observed in the aleurone layer and in the shells, and the minimum - in the center of the endosperm. Since the process of grinding grain into flour is reduced to the separation of the endosperm from the shells, the ash content of the flour can be used to determine the number of shells and aleurone layer that have passed into the flour. Thus, control over the process of separation of the membranes from the endosperm is carried out. The lower the ash content of the flour, the higher its grade. It is an indirect indicator of the ratio of the anatomical parts of the grain. The ash content of soft and durum wheat is practically the same. However, the endosperm of durum wheat still has more than the endosperm of soft wheat. The higher ash content of durum wheat flour is also due to the fragility of its aleurone layer, which partially gets into the flour. The ash content of small and shriveled grains is higher due to the higher content of shells. In hulled wheats, the ash content is higher than in naked wheat. The ash content of the grain of different crops is not the same: in wheat, like in other naked grains, it is small, in hulled cereals it is higher, for example, in rice, 5.0-6.0%. Ash content depends on a number of factors: variety, growing area, soil and climatic conditions, applied fertilizers, etc.
1.8 Determination of glassiness of grain
The vitreous grain is better milled than the mealy grain, that is, the endosperm residues are more easily and more completely separated from its bran particles. Vitreousness characterizes the structural and mechanical properties of the endosperm and grain resistance to destructive forces, affects the grinding process and the conditions for the formation of intermediate products. Grains with a higher glassiness have increased strength and require more energy for grinding.
Vitreousness is taken into account when placing grain in storage facilities and when forming grinding parties. The total glassiness for soft wheat with varietal mills should be at least 50%, with pasta mills - at least 60%, for durum wheat (regardless of the type of grinding) - at least 80%. In addition, the vitreousness of wheat grain processed into cereals is normalized. It should be between 70% and 80%.
Vitreousness is also determined for rice grains. With an increase in vitreousness, the yield of cereals of higher grades increases (the content of the whole kernel in the cereal). At present, the determination of the vitreousness of wheat and rice grains is carried out in accordance with GOST 10987-76 by two methods: using a diaphanoscope; according to the results of inspection of the grain cut. During the test, the total glassiness is determined. The total vitreous index is understood as the sum of fully vitreous and half of the partially vitreous grains.
The discrepancy between parallel definitions should not exceed 5%. In laboratory conditions, the vitreousness of the same soft wheat sample was determined by standard methods and using the "Analyzer of grain products" software and hardware complex. The determination by standard methods was carried out by three independent researchers, and the determination by digital image processing - with three different settings of the internal parameters of the program (two of them were set with a deviation from the recommended method). Then the results were compared and presented in the form of histograms. During the test, the total vitreousness of the wheat grain is determined. The total vitreous index is understood as the sum of fully vitreous and half of the partially vitreous grains.
Determination of the vitreousness of grain is carried out in several ways: determination of vitreousness using a diaphanoscope and by examining the grain cut. Determination of vitreousness using a diaphanoscope. Determination of the vitreousness of wheat grain. To determine the vitreousness, 100 whole wheat grains are isolated and cut across in their middle. The cut of each grain is examined and the grain, in accordance with the nature of the cut, is assigned to one of three groups: mealy, vitreous and partially vitreous. The calculation results are compared with the data of GOST 10987 on the vitreousness of wheat.
Figure 6: Determination of the glassiness of grain
9 Determination of the quantity and quality of gluten
The gluten content in wheat grain and its quality are important indicators characterizing the quality of the grain. Gluten is formed after washing starch, fiber, water-soluble substances from the dough with water and is a dense rubbery mass, 80-90% of the dry matter of which are proteins (gliadin and glutenin) and 10-20% are retained by the forces of sorption starch, sugar, fiber, fat , mineral and other substances. The content of crude gluten in wheat grain ranges from 7 to 50%, its content is considered to be high over 28%. Gluten is washed manually or mechanically.
To assess the technological properties of gluten, along with the quantity, its quality is of great importance, which is a hereditary trait and is less susceptible to the influence of soil and climatic conditions.
The quality of gluten is determined by its physical properties: elasticity, extensibility, elasticity, viscosity.
Elasticity - the property of gluten to return to its original position after removing the deforming effect. To characterize gluten in elasticity, the IDK-1 device (gluten deformation meter) is used. Under the pressure of a load weighing 120 g freely falling on a ball of gluten weighing 4 g for 30 s, a deforming load is created. The elasticity indicators are recorded by the deflection of the arrow on the scale of the device. The higher the elasticity of the gluten ball, the weaker the deformation and the less the deflection of the arrow on the scale of the device.
Table.1 Characteristics of gluten elasticity
If, after washing, the gluten does not form into a ball, crumbles, then it is referred to group III without determining the quality on the device.
In the absence of the IDK-1 device and with a smaller amount of grain, which is often found in breeding practice, when a sample of not 25 g is used for washing gluten, as provided by GOST, but 5-15 g, the quality of gluten is determined organoleptically.
Figure 7: IDK-1
1.10 Determination of the baking properties of flour
Bread flour is a powdery product with a different particle size distribution, obtained by grinding (grinding) grain. The baking quality of wheat flour is mainly determined by the following properties: Gas-forming ability, characterized by the amount of carbon dioxide released over a set period of time during fermentation of dough, kneaded from certain quantities of this flour, water and yeast.
The ability to form a dough with certain rheological properties - the strength of flour. The optimal ratio of flour and water in the dough depends on the ability of flour to form a dough with certain rheological properties. In addition, the rheological properties of the dough affect the operation of the dough dividing machines, the ability of the formed pieces of dough to retain carbon dioxide and the shape of the product during proofing and the first baking period. The volume, structure of the porosity of the crumb and the shape of the finished bread also largely depend on the rheological properties of the dough.
The color of flour and its ability to darken in the process of making bread from it. The color of the crumb is related to the color of the flour. However, light flour can in certain cases also produce bread with a dark crumb. Determination of the baking power of wheat flour by sedimentation sediment. The determination method is based on the ability of flour protein substances to swell in weak solutions of lactic or acetic acids and form a precipitate, the value of which characterizes the amount of protein substances.
In a 100 ml measuring cylinder with a ground stopper, graduated with a graduation of 0.1 ml, add 3.2 g of flour weighed on a technical balance. 50 ml of distilled water tinted with bromophenol blue dye is poured into the cylinder. A stopwatch is turned on (it is not stopped until the end of the determination). The cylinder is closed with a stopper and within 5 s. , shake, sharply moving in a horizontal position.
A homogeneous suspension is obtained. The cylinder is placed in a vertical position and left alone for 55 seconds. Having taken out the stopper, pour in 25 ml of 6% acetic acid solution. Close the cylinder and turn it over 4 times within 15 s, holding the stopper with a finger. Leave the cylinder at rest for 45 s (up to 2 min according to the stopwatch from the beginning of the determination). Within 30 s, the cylinder is turned over 18 times smoothly. Leave the third time alone for exactly 5 minutes and immediately produce a visual reading of the volume of sedimentation sediment with an accuracy of 0.1 ml.
11 Latest laboratory equipment
When we got acquainted with the latest equipment in the course of work in the laboratory, we found that the analyzes carried out by us became much faster and more accurate. Thanks to the creation of the latest technologies, we can immediately determine and give an accurate analysis on the spot, thus we can get the job done much faster. INFRANEO is an irreplaceable device for express-analysis of the most important parameters of grain quality by IR absorption. It allows you to accurately determine the quality of whole grain, flour and other processed products in record time in less than 1 minute.
Principle of operation: The analysis of whole grains and flour is carried out using the method of light transmission in the infrared region, in the wavelength range from 750 to 1100 nanometers using a monochromator. Analyzer advantages: Reliable and accurate results: Highest quality performance associated with high precision optics. Simple, fast and convenient. INFRANEO can store over 50,000 measurements on the hard disk. You can predict a new parameter (Greens, Ash, Gluten, etc.) on already analyzed samples at any time without deleting your current results. Thanks to the built-in hard disk (from 40 to 500 GB), the number of saved results is practically unlimited. All statistics and classification of results by date, sample name, time, etc. allow you to track and fully monitor the analyzes performed in the best way.
Figure 8: Moisture Meter
Figure 9: Laboratory sieves.
Figure 10: Drying oven.
grain flour vitreous elevator
II. Grain-receiving and grain processing enterprises
1 Laboratory and its equipment
Agrimer Astyk LLP is a modern enterprise that accepts and stores grain crops. From commodity producers, the incoming grain to the elevator is cleaned and worked up to meet the requirements of GOST. All operations of the technological process for receiving and placing grain crops at the enterprise are fully automated and mechanized. The elevator has a well-equipped laboratory certified by the State Standard of the Republic of Tatarstan, which is equipped with the necessary equipment to determine the quality of grain. There is also a laboratory on the territory of the elevator, where accurate analyzes are carried out. The structure of the elevator includes: a weighing tower, a working tower, a drying department, an administrative building, a laboratory, a shipping department, etc.
2 Elevator operation
An elevator is a facility for storing large quantities of grain and bringing it to a conditioned state. The elevator is also a highly mechanized silo type granary. It includes a complex of structures connected by common production processes, of which the main ones are: acceptance; weighing; storage; grain release; cleaning; drying; sorting. The main production buildings and structures of elevators include: a working building, silo buildings with conveyor galleries, facilities for unloading grain from railway, road and water transport and loading grain on the means of these types of transport; facilities for drying grain, facilities for storing and loading waste on vehicles and railway vehicles.
The composition of a typical elevator: weighing, receiving compartment (for unloading railway or motor vehicles) is an inlet pit of various volumes of a passable or non-passable type; a working tower, it houses machines for preliminary, primary and, if necessary, secondary cleaning of grain, as well as an aspiration system for cleaning from light impurities; drying department, includes tanks for accumulation of wet and dry materials, as well as the required number of dryers of various designs with burners for the required type of fuel; storage compartments, in a modern elevator, are silos (cans) of the required capacity located in one row, which allows you to store different crops or varieties of the same crops in one elevator; the shipping department, as a rule, is a system of hopper bunkers, for shipment to railway or motor vehicles; transport equipment connects all elevator routes (by elevators and conveyors of various types and modifications) electrical and automation systems, includes control cabinets, frequency converters, sensors, electrical cable products, lighting; administrative building, laboratory, fire tank and others required by the standards, buildings and structures.
Figure 11: Elevator
Grain elevators - equipment that is a vertical conveyor for moving grain and bulk cargo. The principle of operation and design of grain elevators is similar to that of bucket elevators.
They are used as a vehicle at flour mills, feed mills, elevators, grain warehouses and other industries.
Figure 12: Grain Elevators
3 Storage facilities and equipment used in them
Grain is stored in special storage facilities, grain warehouses. Before loading the storage facilities with grain of the new crop, they are disinfected - disinfestation is carried out using wet, aerosol or gas methods. All equipment, vehicles, containers are subject to disinsection. Before loading into storage facilities, the grain is dried, cleaned of weed seeds, lumps of earth and other debris and cooled (up to 12-15 ?C and below). In some cases, chemical preservation of feed grains is carried out. The storage of grain and products of its processing is based on the principle of partial or complete suppression of the flow of unfavorable processes in the mass of products, the main physiological image. The implementation of this principle must know the storage objects, principles and methods of storage. Mainly in long-term storage silos, granaries and warehouses.
2.4 Warehouses and grain products
SILOS is a storage compartment, in a modern elevator it is (cans) of the required capacity located either in one row. The silos are interconnected with the work building, where the main technological and transport equipment is located. Grain from the receiving hoppers is lifted by conveyors or vertical lifters (noria) to the top of the working building, weighed, cleaned of impurities, dried in grain dryers and sent along the upper conveyor to above the silo conveyors, which dump it into the silos. Grain is unloaded onto the lower conveyors (they are installed under the silo floor) through holes with funnels in the bottoms of the silos.
5 The process of cleaning and sorting grain
Separators of the BIS type - designed for the primary cleaning of wheat (and other crops) grain from impurities that differ in width, thickness and aerodynamic properties using sieves and air flow. Separators for primary grain cleaning are used in grain preparation departments and at elevator and flour mills, including as part of complete equipment for newly built mills.
6 Process of operation of a grain dryer
Fully mechanized dryer control system with subsequent cooling. The dryer is very easy to use and requires little maintenance. The dryer can also operate in air suction mode. In this case, dust is separated separately. The speed of grain passing through the automatic unloading mechanism can be adjusted depending on the processed crop without the use of additional devices. The dryer runs on diesel fuel (diesel fuel). After taking a sample from the conveyor, drying department, separator and carry out the corresponding analysis in the laboratory. Having received the result, you must immediately inform the dispatcher about this, who, in turn, regulates the moisture content of grain and oilseeds. Before taking a sample, you need to remember to turn off and on the fan every time so that the grain does not burn out. We take a sample from the dryer every hour. We carry out the analysis through infraneo and write the data to the log. Then we pour 2 caps into a container for an average day. And after the analysis, you need to inform the dispatcher about the humidity so that the grain does not dry out and bring it to the desired condition.
III. Technochemical analysis of grain. Weight analysis
The driver transfers all the waybills to the weighing machine to the weighing operator, who enters the weighing results and data from the waybills into the journal. The log records the name of the supplier, the type of product, the state number of the car, the date, time of arrival, gross weight, tare, net, time of departure. The gross weight, tare, net, as well as the warehouse number are also indicated on the back of the first copy of the consignment note. The rest of the copies indicate the net weight and the warehouse number. All invoices are returned to the driver, except for the first copy. At the end of the operating day, the weigher takes all invoices to the accounting department. The quality of cereals, legumes and cereals is assessed by three main indicators: conditional starchiness, weediness, moisture. When grain is used for malt, it is also evaluated according to its germination ability and germination energy. When the grain is released into production, the average daily samples of grain supplied to production are analyzed every day by road transport from the warehouse of the plant, from the station warehouse or directly from the supplier. In addition, the plant constantly monitors the accuracy and objectivity of determining the quality of grain for the reporting period, analyzes average monthly samples that are stored for 2 months.
1 Technochemical analysis of grain
Technochemical analysis includes: Weighing scales; Sample selection; indicators of grain freshness; grain moisture; grain contamination; nature; size; fine grain. Pests of grain stocks: Mineral substances of grain; acidity; physical properties; grain mass.
3.2 Sampling
A batch is understood as any quantity of grain, uniform in quality, intended for simultaneous acceptance, delivery, shipment or simultaneous storage. The sampling of an average sample begins with a spot sample, which is a small amount of grain taken from a lot at a time from one place. Samplers and hand-held probes are used for sampling point samples. The aggregate of point samples is a combined sample, from which an average sample is then isolated, the mass of which should not exceed 2.0 + -0.1 kg. If the mass of the combined sample is not more than 2 kg, then it is at the same time an average sample. Isolation of the average sample from the combined is carried out manually.
Pour the combined sample onto a table with a smooth surface, distribute the grain in a square shape and mix thoroughly three times using two short wooden planks with a beveled edge, grabbing it from the edge and pouring it into the middle. Then the grain is again distributed in an even layer in the form of a square and divided diagonally into 4 triangles with a bar. The grain is removed from the 2 opposite ones, and the other two are collected together, mixed and the division is continued again until there are 2 kg of grain in the two triangles, which will make up the average sample.
To determine individual indicators of grain quality, a small part is isolated from the average sample, which is called a sample. Qualitative assessment of grain.
Organoleptic characteristics: taste, shape, color, smell. Physicochemical: humidity, weight of 1000 grains, bulk density - nature, vitreousness, contamination, ash content, pest infestation, metal impurity content. Technological assessment, baking properties.
Sampling and preparation of samples.
In order to correctly make an assessment, it is necessary to correctly compose a sample.
Lot - a certain amount of grain stored in the warehouse, intended for acceptance and dispatch of the same type and uniform quality.
First, the recesses are taken from the batch - a small amount of grain taken at one time, these recesses are mixed, an initial sample is obtained. If the mixture of grooves is large, then the medium is chosen from it. In appearance - smell, shine, taste - more often they change together. The color changes in immature, with improper cleaning and storage - the shine is lost, the smell is specific or grain (garlic, granary, moldy). Taste - bitter, sweet, salty and sour, normal - insipid, sweetish - sprouted grain, sour - with increased acidity, bitter - with weeds.
Figure 13: Sampler.
3 Indicators of freshness of grain
The freshness of the grain is determined by visual inspection of its sample. The color, shine, smell, taste are used to judge the good quality of the grain or the nature of the defects present in the test batch. Fresh, good-quality grain has its characteristic color and shine. Therefore, the color of the grain is at the heart of the commodity classifications adopted in the standards. Normal grain and oilseeds of each crop have a characteristic natural color, luster and odor. Therefore, state standards stipulate that grains and oilseeds must have the normal color and odor characteristic of the grain or seeds of the crop; the taste of the grain is also taken into account. These signs are indicators of its freshness, usefulness of consumer properties. The color and smell of grains and oilseeds can vary significantly under the influence of unfavorable conditions during maturation, harvesting, transportation, drying and storage. Improper harvesting can cause grain to lose the shine of healthy grain. The grain changes color under the influence of frost, when it is not yet fully ripe and is on the root, as well as under the influence of dry wind, prolonged stay in rolls, overheating in grain dryers, etc.
The freshness of the grain is the smell of the grain. The healthy grain of each crop has a specific smell. Most crops have a weak odor, while essential oils have a pungent odor. If the grain contains wormwood, garlic, sweet clover, then there may be a pungent smell, the smell appears with a large amount of moisture. If, during improper storage, the smell of the grain changes. When the smell changes, it happens (gnarly, musty,) and leads to a change in the chemical composition.
4 Grain moisture
For the main grain crops: wheat, rye, barley, oats, buckwheat, the following grain conditions are adopted for moisture content:
Dry - up to 14%
· medium dryness - over 14% to 15.5%
· wet - from 15.5% to 17%
Raw - over 17%
The state of humidity is used for placement and accounting of grain during storage. Increased humidity (over 14-15%) leads to a sharp decrease in seed germination, and sometimes quality.
Figure 14: SESH-3
5 Grain contamination
Impurities in the grain mass complicate the storage and processing of grain, worsen the quality of the finished product. All impurities are divided into two main fractions: weed and grain. Weed impurities are useless or harmful to the diet. In addition, it includes grains from other crops that cannot be used in the same way as grain from the main crop. Grain admixture has a reduced value in comparison with normal grains of the main crop, but can be used for the intended purpose of the latter.
The content of weed, harmful and grain impurities is determined by state standards for grain of each crop. The rate of impurities is linked to the intended purpose of the grain. Depending on the percentage of impurities in the grain, it is divided into two groups: grain that meets basic conditions, and grain that has deviations in quality within the limits of restrictive conditions. Various production machines are used to clean grain from impurities.
The separation of weed seeds, like other impurities, is based on the difference in their physical and mechanical properties from the properties of the grains of the main crop. The separation is the simpler and more complete, the more the properties of impurities differ from those of the grain, and, conversely, the more difficult and less complete, the less this difference.
6 Nature, size, fine grain
The nature of the grain is the mass of 1 liter of seeds in grams. The nature is determined on a liter purke with a falling weight - it is expressed in grams per liter or on a 20-liter purke - expressed in kilograms of one hectoliter of grain. The size of nature is influenced by: impurities, the state of the surface of the grain, the shape of the grain, size, density, moisture, filminess, maturity and completeness of the grain, the mass of 1000 grains, evenness. The nature roughly shows the degree of fulfillment of the grain.
Size
The linear dimensions of the grain determine its size, which is the most important indicator of the quality of the grain. Coarse grain has more endosperm and fewer shells, and, consequently, a higher yield of finished products from grain. Coarseness is related to the chemical composition of the grain and its other characteristics. It can be expressed not only by the linear dimensions of the grain, but also by its volume and weight of 1000 grains. Linear dimensions are understood as the length, width and thickness of the grain and seed. The length is the distance between the base and the top of the grain, the width is the greatest distance between the lateral sides and the thickness is between the dorsal and ventral sides (back and abdomen). The set of linear dimensions is also called coarseness.
Coarse grain gives a higher yield of finished products, since such grain has more endosperm and fewer shells.
Of the three dimensions (length, width and thickness), the thickness most characterizes the milling properties of the grain.
3.7 Pests of grain stocks
All pests of grain stocks are divided into two types: vertebrates (chordates) and invertebrates (arthropods). Vertebrate pests are represented by two classes: mammals and birds. Invertebrates are also represented in two classes: insects and arachnids. The main difference between insects and arachnids is the number of legs: insects have three pairs of legs, and arachnids have four pairs. In addition, the majority of arachnid pests of grain stocks lack visual organs.
Figure 15: Barn pests:
8 Mineral substances of grain
Grain minerals are part of the ash obtained as a result of complete combustion of ground grain at a temperature of 750-850 ° C. Ash content has different meanings, both for individual anatomical parts of the grain, and for different crops. Most of the minerals are concentrated in the shells, the aleurone layer of the wheat grain, as well as in the germ. The ash content of the grain of hulled crops is higher than that of naked ones. In cereal ash, the main element is phosphorus, there is also a lot of potassium and magnesium. The ash contains very little calcium. The presence of minerals in grain products affects their nutritional value and determines the technological properties of grain. The amount of mineral substances in the grain varies widely and depends on the soil, climate, fertilizers applied, and the variety and type of plant.
9 Acidity
Acidity is of great importance for determining the quality of grain. Acidity is determined by a chatterbox: aqueous, alcoholic or ethereal extracts from ground grain. Acidity is due to the presence of acid-reacting substances in the grain. This group includes amino acids, proteins, fatty acids, organic and inorganic acids. The grain contains such organic acids as malic, oxalic, lactic, aconitic, etc. When added to a suspension or a solution of alkali, the acid binds to it. Normal healthy grains are usually low in acidity (1 to 3 °). Under unfavorable storage conditions (germination, self-heating) or with very long storage, acidity increases. Thus, acidity is an indicator of the freshness of the grain. It also increases during the storage of flour, cereals and compound feed, especially if the storage conditions have been violated. Acidity is expressed in degrees. One degree of acidity is equal to one milliliter of normal alkali (sodium hydroxide) used to neutralize the acid in 100 g of ground grain (flour) during titration. Acidity is determined according to GOST 10844-74 “Grain. Method for determining acidity by talker "The method consists in titration of acid-reacting substances of grain with alkali. In this case, titrate a water mash (suspension of ground grain).
3.10 Physical properties of grain mass
The grain mass is a set of grains of the main crop of various sizes and completeness, grains (seeds) of other cultivated plants, various impurities of mineral and organic origin, microorganisms, air in the intergranular space, and sometimes pests of grain stocks. The presence of such different components in the grain mass gives it specific properties that must be taken into account during processing and storage. All properties of the grain mass are divided into two groups: physical and physiological. The grain of the main crop and its contaminating impurities differ in the following physical and mechanical properties: weight; windage (resistance exerted by individual seeds to the air flow acting on them); dimensions (width, thickness and length); shape (round and angular); surface properties (rough and smooth) and magnetic properties.
Looseness.
This is the ability of the grain mass to move on any surface located at an angle to the horizon. Free flow is characterized by the angle of repose, i.e. the angle between the diameter of the base and the generatrix of the cone, resulting from the free fall of the grain mass on the horizontal plane (Table 1). The flowability of the grain mass is influenced by many factors, namely: the shape, size, nature and condition of the grain surface (particle size distribution and characteristics), moisture content, the amount of impurities and their species composition, the shape and condition of the surface of gravity pipes. Self-sorting of the grain mass occurs when moving and shaking, when loading and unloading warehouses and silos of elevators. Self-sorting is understood as the ability of the grain mass to lose uniformity when moving and in free fall.
With the free fall of solid particles of the grain mass, its self-sorting is facilitated by aerodynamic properties - the speed of hovering. It is customary to understand it as the speed of the air flow in the vertical channel, at which the weevils are in suspension (soar).
For wheat, the soaring speed is 9-11.5 m / s, while for dust particles and chaff it is much less. When loading, heavy grains of wheat fall quickly down and settle in the center of its section, while light particles of impurities soar in the air, slowly sinking and roll down the inclined conical surface of the embankment to the walls. When the grain is discharged from the silos, the heavy central part of the grain embankment first comes out and only then the peripheral (near-wall with weeds, sex, dust) with less valuable, puny, underdeveloped grain.
Flow characteristics of various crops. Self-sorting of the grain mass worsens the conditions for its storage and processing. The openness is an important indicator that should be taken into account when storing grain masses. On the one hand, thanks to wells, grain embankments can be processed with air (during drying, ventilation, aeration). In others. The presence of oxygen in the air of the intergranular space contributes to the preservation of the viability of seeds. On the other hand, the larger part of the embankment is occupied by the wells, the less grain in the same volume, therefore, a large storage capacity is required.
The hygroscopicity of the grain mass is especially important to consider during handling and storage. As a result of the interaction of the grain mass with the environment, the moisture content of the grain is continuously changing until equilibrium is established.
3.11 Analysis of grain of cereals and buckwheat
Cereals are an extremely diverse group of field crops. It includes eight major botanical genera. Definition of breads by grain: For the convenience of study, cereals can be divided into two groups that differ from each other in many morphological, biological and economic characteristics. The first group is made up of wheat, rye, barley, and oats, the second group - millet, corn, sorghum, rice.
Table 2.1
Bread of the first group Bread of the second group 1. There is a clear longitudinal groove on the ventral side of the grain. 1. The longitudinal groove on the ventral side of the grain is absent. 2. The grain germinates with several germinal roots, the number of which is not the same in different genera. 2. The grain germinates with one germinal root. 3. The lower flowers are more developed in the spikelet. 3. The upper flowers are better developed in the spikelet. 4. The demand for heat is less. 4. The demand for the body is higher. 5. The demand for moisture is greater. 5. The demand for moisture is less (with the exception of rice). 6. There are winter and sound forms. 6. There are only sound forms. 7. Plants (long day). 7. Plants (short day).
12 Legume seed analysis
Peas, beans, lentils, rank, chickpeas, soybeans, beans are of food value. The seeds of leguminous crops are covered with a dense shell on the outside, under which there are two cotyledons connected by a sprout. Legumes contain: proteins 30% or more (valuable in composition, since they are rich in essential amino acids), carbohydrates up to 60%, fat about 2% (except for soybeans containing up to 20% fats, up to 30% carbohydrates, up to 40% proteins) ...
The disadvantage of legumes is the slow digestibility of their seeds (from 90 to 120 minutes). To accelerate the digestibility, the seeds of some legumes (peas, lentils) are crushed, i.e. remove the seed coat. This cuts cooking by about 2 times.
Peas originate from Afghanistan and East India, The fruit of the pea - the bean - consists of the valves and seeds. According to the structure of the bean valves, pea varieties are divided into sugar and shelling. Sugar beans are used for food together with seeds in the form of so-called shoulder blades. The shells of the shelling varieties are not edible. When the seeds ripen, the bean shells are easily dehulled; therefore, these varieties of peas are called shelling peas.
Hulling varieties are subdivided into cerebral varieties, which in milk ripeness are used to prepare canned vegetables (green peas), and smooth-seeded varieties, which in full maturity are divided into two types: food and fodder. Food peas, depending on the color of the cotyledons, are white, yellow and green. According to the size of the seeds, peas are divided into large, medium and small. Pea seeds retain their nutritional and taste properties for 10-12 years.
Beans are divided into three types by color: white, colored monochromatic and colored variegated. Lentils are the oldest agricultural crop; they have been known in Russia since the XIV century. The seeds are 5 mm in diameter and resemble a biconvex lens. There are two types - northern, growing in the central regions of Russia, and southern, grown in Ukraine. Soy is a universal world legume. Soy is used to produce flour, butter, milk, cheese; it is added to confectionery, canned food, sauces and other food products. Soy is used only after industrial processing. Natural soybeans are not edible. Chickpea and rank are in many ways similar to peas. They are eaten, like peas, fresh, boiled and fried. Canned food is made from them, and biscuits and other products are made from flour.
Figure 21: Beans of various cereal legumes: a - peas; b - lentils; c - chickpea; g - beans; d - vetch; e - broad beans; g - soy; h - lupine
The main factor that determines the flow of bulk material is the dynamic roof over the hole. During the experiments, a reflective cone was placed in the zone of formation of a dynamic arch, the dimensions and height of the installation of the cone were determined depending on the best effect of a uniform outflow of grain for a given bunker.
The consumption of bulk material, as shown by experiments, does not depend on the initial density of its packing. Thus, it can be assumed that the consumption of bulk material during its free outflow from the hole is determined by the value of the underwater volume above the hole or by an increase in the number of holes for the release of grain from the silo or hopper, and hence the uniform high-quality release of grain (since the grain mass is heterogeneous, the heterogeneity changes height during release).
13 Analysis of oilseeds and essential oilseeds
Definitions of oil plants by seeds: The seeds of oil plants are considered to be either genuine seeds in the botanical meaning of the word, or fruits. In order to avoid mistakes and confusion in the further definitions of these parts of the plant, it is necessary to use botanical terminology, strictly different fruits from seeds. The fruits and seeds of oilseeds are easily distinguishable from each other, except for the cruciferous oilseed group, which is considered separately. Nevertheless, for the first acquaintance with the plants of the oilseed group, it is advisable to establish different ones between the fruits and seeds of certain species, proceeding in the future to the study of the rest of the plants. The general characteristics of the fruits and seeds of oilseeds, due to their great diversity, is difficult and does not seem necessary. Signs of fruits and seeds of oil plants.
Identification of oil-bearing plants by seedlings Oil-bearing seeds, placed in proper conditions of humidity and heat, begin to germinate when oxygen is available from the air. Seed germination begins with the fact that the root, breaking through the shell of the seed or both the seeds and the fruit, if the fruits are sown (sunflower, safflower,), comes out, penetrates into the soil, bent downward with its end (growth point), and takes root in it, continuing to grow farther. Almost simultaneously, the usually curved other hypocotyl knee begins to lengthen and grow, a segment of the stem between the embryonic root and the cotyledons. This hypocotal knee is extremely short in embryo.
Having begun to lengthen simultaneously with the germination of the seed, it, after rooting of the embryonic root, stretches as it grows to the day surface and the cotyledons. Here, above the soil surface, the arched hypocotyl knee straightens, and the cotyledons located at its end open and turn green, turning into the first fake leaves, or as they are called, cotyledon leaves. After the cotyledon leaves open and begin to assimilate, the first true leaves begin to form from the bud located between them from the point of plant growth.
Definition of essential oil plants: Mint propagates mainly vegetatively. It is usually planted with rhizomes; mint seeds are not commonly used in agricultural production. The seeds of essential oil plants in the umbrella family are fruits or parts of the fruit into which it breaks down. The fruits of all these essential oil plants of the umbrella family are small (3-5 mm), spherical or elongated. Each fruit consists of two dry, non-opening fruit trees, each containing one seed.
Between the rafts is the so-called column, usually divided from top to bottom into two parts. In some species and varieties, the fruits, when ripe, split into two fruit growers, hanging one at a time on the divided parts of the column. On the surface of the fruit, there are 10 more or less clearly defined longitudinal ribs.
Determination of essential oil plants by seedlings: During germination of seeds of essential oil plants of the umbrella family, the cotyledons are carried to the soil surface. Separated cotyledonous leaves are somewhat different from species to species, but generally elongated. After the appearance of the cotyledonous leaves, the first true leaves develop from the bud located between them. These leaves have more distinct differences in different species and unfold in some species in pairs, in others one at a time. The first true seedling leaves make it easier to identify plants by seedling.
14 Analysis of seed (sowing) grain
A batch of seeds is a certain amount of seeds of uniform quality (one crop, one variety, one harvest). Probes of various shapes or a sampler are used as sampling devices. From the increments, a pooled sample is made up, which is a collection of mixed increments. An average sample is isolated from the combined sample by quartering (cross-division). The mass depends on the size of the seeds and is 1000 grams. The average sample is isolated in 3 copies. The first is used to determine the purity, germination, viability and weight of 1000 seeds), the second is used to determine the moisture content and infestation by pests, the third (weighing 200 grams) is to determine the infection of seeds with diseases. Taking a sample of the average sample is drawn up by the act of selection (in duplicate). Based on the results of laboratory analysis of average samples, the seed inspections issue documents on the sowing qualities of seeds.
IV. Technological analysis of grain processing products
1 Sampling flour for analysis
Flour samples are taken with a flour probe, which is introduced towards the middle part of the bag, chute down, then rotated 180 ° and removed. The total mass of the recesses taken should be about 2 kg. The samples are placed in a clean bag or in a jar with a tight-fitting lid. The accompanying documentation, which is inserted inside the bag or jar, must indicate the name of the type and grade of the product, the place and date of its receipt, the place and date of sampling, as well as the position, surname and signature of the person who took the sample. Determination of the organoleptic properties of flour 20 g of the test flour is scattered on a piece of paper, warmed with breath, and then examined for odor. To enhance the smell, the same amount of flour is poured into a glass, poured over with a small amount of hot water at a temperature of 60 ° C, after which the water is drained and the smell is determined.
Wheat flour should have a white color with a yellowish tinge; only wallpaper flour of 96% grinding is allowed to have a grayish tint with noticeable particles of shells. Smell typical of normal flour; should not be felt, the smell of mold, mustiness, etc. The taste is slightly sweet. No crunch should be felt when chewing.
Determination of the acidity of flour: Into a conical flask with a capacity of 100-150 ml, add 5 g of flour, 50 ml of distilled water and stir until the lumps of flour disappear completely. Then add 2-3 drops of a 1% alcoholic solution of phenolphthalein and titrate with 0.1 N. solution of potassium hydroxide or caustic soda until a slightly pink color persists for 1 min. The acidity of flour is determined by the acids in it and is expressed in degrees. Degrees of acidity indicate the amount of 1N. solution of caustic soda or caustic potassium (ml), used to neutralize acids in 100 g of flour.
Determination of flour moisture content: 5 g of flour is added to tared metal or glass bottles, after which they are placed in an open oven for 40 minutes in an oven at a temperature of 130 ° C. The weighing bottles removed from the thermostat are closed with lids and placed in a desiccator with dry calcium chloride or concentrated sulfuric acid until completely cooled, and then weighed. The moisture content of flour should not exceed 15%
Determination of gluten. Gluten is a hydrated protein-fat complex, which consists mainly of two protein substances - gliadin and glutenin. The baking properties of flour depend on the quality and quantity of gluten. A sample of 25 g of flour is transferred into a mortar, 13 ml of tap water at room temperature is added and kneaded with a pestle until smooth. At the end of the kneading, the pieces of dough that have adhered to the pestle are returned to the mortar with a knife, and the dough formed in the mortar is crushed with hands and rolled into a ball. Leave for 20 minutes. then they take the dough in their hands and, carefully kneading it, they begin to wash it from starch and shells either in a container with water, or under a weak stream of running water over a thick sieve. If the gluten is washed in a container, then the water is changed as it gets dirty, filtering through a sieve. Pieces of the torn off gluten are added to the total mass. Gluten is considered washed out if clear water is squeezed out of it. Next, the gluten is weighed, then washed for 5 minutes under running water, after which it is squeezed out and weighed again. If the difference between the first and second weighing does not exceed 0.1 g, the gluten washing process is considered complete.
The amount of gluten as a percentage of the initial mass of flour is determined by the formula:
where a is the mass of gluten, g; b - sample of flour, g.
Indicators of the quality of gluten are its color, extensibility and elasticity. The color distinguishes between "light", "gray" and "dark" gluten. To determine the extensibility from gluten, weigh a piece weighing 4 g, make a ball out of it and place it in a cup of water at room temperature for 15 minutes, and then, taking the ball with three fingers of both hands, slowly stretch the gluten over the ruler, fixing the maximum extensibility at the moment of rupture. Depending on the degree of extensibility, short, medium and long gluten are distinguished, the extensibility of which, respectively, is up to 10 cm, from 10 to 20 cm and "more than 20 cm. The elasticity of gluten is judged by the rate of recovery of its original shape after squeezing or a small one, by about 2 see stretching.
The freshness of the flour. It is determined by the nature of the color of the chloroform layer (using the Novus device, which is a special test tube with a clavate thickening at the bottom. At the bottom of the test tube there is a ring-shaped thread, in the middle part there is a circular division, as well as a number of divisions extending up and down from the circular one. The test tube is filled with chloroform until circular division, add 1 g of the test flour, close with a stopper and mix, turning the bottom upside down two or three times, then set it in a vertical position for 30 minutes.) Fresh flour stains chloroform in a milky white color. If the flour is spoiled, then the chloroform briefly turns dirty brown, after which it becomes transparent.
2 Sampling and analysis of cereals
The quality of cereals is established for each homogeneous batch based on the results of laboratory analysis of an average sample. To establish individual indicators of product quality, a sample is taken - a part of an average sample of cereals. Select groats from the sewn bags with a probe from the upper, middle and lower parts. The probe is inserted towards the center of the bag from bottom to top, groove down, then turned 180 ?and take out. From coarse calico bags with linen lining, the recesses are taken from the neck. One package of cereals is taken from each packaging unit, which is a recess. The selected recesses are joined to form the initial sample.
Then the original sample is leveled with a thin layer and divided into four triangles using a plank. From the two opposite triangles, the products are removed, and from the rest are combined until about 1.5 kg. According to the average sample, organoleptically determine: color, smell, taste, crunch.
3 Sampling and analysis of compound feed
The selection of compound feed is carried out for control for compliance with the current regulatory documents on the content of gamma and beta-emitting radionuclides. Sampling of agricultural raw materials or feed at the optimal cost of time and money should ensure the representativeness of samples that most fully and reliably characterize radioactive contamination. Sampling is carried out by specialists with the necessary training in the field of radiation monitoring.
The following tools and equipment are used for sampling: sickle, knife; ladle, mug; bag and carriage probes; bulk feed samplers; tweezers; metal or plastic scoops; cylindrical tubes with an inner diameter of 9-10 mm; jars with tight-fitting lids; wooden planks with beveled edges. The instrument used must be clean and, after selection, subjected to decontamination with detergents, followed by dosimetric control.
Sampling of agricultural raw materials and feed for radiation monitoring includes: selection of point samples; preparation of a combined sample; separation of the middle sample. The mass or quantity of the average sample taken for analysis is governed by the measurement procedure used in the radiation monitoring laboratory conducting the measurements. The spot samples are mixed and a pooled sample is formed. An average sample with a mass of at least 5 kg is formed from the combined sample. The spot samples are mixed and a pooled sample is formed.
An average sample with a mass of at least 3 kg is formed from the combined sample. Spot samples of concentrated feed are taken from places of production and storage in accordance with GOST 13496.0. Spot samples are mixed and a combined sample is formed. An average sample is formed from the combined sample with a mass of at least 2 kg. After sampling, average samples of agricultural raw materials and feed are packed in boxes, box pallets, fabric and plastic bags. For arbitration tests, the mass of the average sample of agricultural raw materials and feed is doubled.
Conclusion
She was instructed in fire safety and complied with all safety requirements.
During my internship at the enterprise, I studied the laboratory equipment, the principle of their work. I got acquainted with the whole process of receiving, storing and shipping grain. In the laboratory, I learned how to analyze grain for its quality, moisture, contamination, pest infestation, determined gluten, glassiness, filminess, learned how to correctly take a sample both with a probe and with an automatic sampler. She studied the operation of a mine grain dryer, triers, separators and the principle of their operation. Studied the whole process of receiving, shipping and drying grain.
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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 norm 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 in agriculture is divided into real or selective, wild or spelled. Both wild and breeder wheat are classified into hard and soft wheat types. Each breed and subspecies of cereals has its own characteristics, chemical and physical properties of the grain. To streamline the indicators of grain crops in Russia, state standards have been developed for each type of cereal.
Real wheat is firm and flexible, with a strong stem and ear. During threshing, the flower films are quickly separated from the grain. The spelled is distinguished by its fragile and brittle straw, dense structure: during threshing, the films are almost inseparable from the seed.
Both selective and wild varieties are classified according to grain quality, including English and Polish wheat, into hard and soft. Hard grain differs from soft grain in chemical composition, biochemical properties and baking qualities.
GOSTs for wheat seeds, developed during the Soviet era, are constantly revised and supplemented in order to correspond to real time and to monitor continuous work to improve the culture. All changes and innovations are published in the annual index of national standards.
The current GOST R52554-2006 “Wheat. Technical conditions "gives recommendations for its cultivation.
The main provisions of the standard also describe internal types that differ in natural characteristics. The values of the wheat classes are necessary to determine and approve the technological and nutritional, commercial properties. Variable indicators such as glassiness or moisture content of the seeds are used to determine the subtypes of the culture.
Grain classification
Wheat grades are determined by the worst value after sorting, cleaning and drying the seeds. GOST 93-53-90 provides for a commodity classification of a crop, which is characterized by flour-grinding and baking properties.
For soft varieties, there is also a conditional 6 class. Separation by quality and chemical composition is necessary to improve the production of flour and cereals with a good yield. Wheat classification in Russia provides 5 classes for durum varieties.
Soft wheat of the highest and first two classes is called strong and is used for baking bread varieties, to improve flour from weak grain. If the indicators of class 3 wheat give a gluten content above 23%, then it is used to produce high-quality flour without admixtures of stronger varieties. Wheat class 4 is a cereal with a weak chemical and baking properties. Flour from such grain necessarily requires the addition of strong varieties. Wheat grade 5 - grain intended for non-food purposes (livestock feed, feed production or processing for glucose, etc.).
Classes 2-4 of durum wheat are defined as soft 4 classes if the amount of admixture of seeds of other plants (including cereals) is higher than 15%.
Since 1995, Grade 4 grain has been divided into 2 additional groups. This is due to poor productivity and a crisis in agriculture. The first group includes seeds with a gluten level of 21 to 33%. Such seeds are used for the production of varietal flour. The second group includes wheat seeds with 18 to 21% gluten, which are used as forage or for the production of flour with the addition of strong varieties.
Durum wheat is used more for the production of pasta, desserts and elite breads. Soft - for bread and bakery, confectionery products.
Wheat types
The existing 5 types of wheat differ:
- Color: depending on the type of seeds are from white, then brown-red;
- Botanical subtype.
The first 4 species have their own subspecies, including wheat seeds, similar in shade and vitreousness. The classification of grain by natural characteristics of types and subtypes also distinguishes 5 groups. Group 1 includes soft spring wheat with glassiness:
- More than 75% - the grain has a dark red center;
- 60 to 75% - the middle of the seeds is red;
- Up to 60 from 40% - the middle of the grain is pale red;
- Below 40% is the middle with a yellow tint.
Group 2 of spring wheat includes 2 subtypes:
- With a glassiness of over 70% and a rich amber consistency;
- With amber and light amber consistency. The glassiness index is not regulated.
Group 3 includes all subtypes of soft red-grain winter wheat, and the same characteristics apply to it as for group 1. Group 4 includes winter varieties with a white color of the fruit shell. Group 5 - only hard winter varieties.
In cases where harvesting is carried out ahead of time or due to improper storage, the grain may change color. This phenomenon is called powdery grain discoloration.
Wheat grain quality
In accordance with the current GOST 13586.3-83, grain samples for assessing the quality of grain are taken from a batch during loading or unloading. Healthy wheat grain without mold, traces of fungus and spores, bacteria. It is solid, without chips, cracks and other mechanical damage. Has a flat and smooth surface of the color corresponding to the type. The smell of wheat seeds is rich-bready, without sour, bitter or chemical notes.
The main indicator characterizing the class of wheat grain and its nutritional value is protein. Its content depends on the breed and type of cereal, it can reach up to 23%. Solid varieties are richer in protein, and the highest amount of protein is contained in seeds of the 1st class. The minimum is set at 14%. For grade 5, the minimum protein content is 10%.
In the bakery industry, the gluten content is of great importance. It determines the firmness, elasticity and taste of the bread. To control gluten, an indicator of its mass fraction in grain is used. The minimum quantity is set only for the first 3 classes of wheat. For soft varieties of the first class, the gluten content is at least 32%, class 2 wheat must have at least 28%, 3 - at least 23%. Indicators for hard varieties: 28%, 25% and 22%, respectively. For grade 5 wheat, both hard and soft, the gluten level must be at least 18%.
The vitreousness of the grain affects the milling qualities: the yield of the highest grade flour and its cereal-forming ability. According to the results of the analysis of the consistency of endosperm, wheat is classified as glassy, partially glassy or mealy. The definition of vitreousness is detailed in GOST 10987-76. It contains a list of equipment necessary for the analysis of the equipment, the exact weight of the sample is given - 50 g, the maximum moisture content - 17% and two methods of carrying out the procedure. Vitreousness is determined either with a diaphanoscope or manually.
The color of the healthy grain of the type or subtype is used as the reference color for each class. For the first four grades, first degree discoloration is acceptable under certain conditions. Feed wheat does not have a regulated seed color parameter.
To determine the size of the seeds, a standard is used - the mass of 1000 grains. The indicator depends on the size of the seeds, the stage of maturity and completion. The mass is calculated according to GOST 10842-89.
The moisture index is related to the chemical composition: the less water in the seeds, the higher the concentration of nutrients and the nutritional value of the product. The moisture content of the grain is determined by GOST 29027. The method for determining the moisture content of grain consists of the selection of a sample, its dehydration and weighing before and after drying. Additionally, moisture meters can be used. These devices are able to determine the moisture content of the seed in the range from 5 to 40%, and the error is less than 1.5%.
Grain batch composition
Wheat seeds of each variety may contain impurities from other varietal species. For the first 4 classes of spring crops of soft varieties, the level of impurities is not more than 5%, for the 5th class - up to 15%. For hard spring varieties, the established maximum is 5%. If there is more biological plant pollution, then wheat is classified as a mixture of cereal species and the percentage composition of each cereal is indicated.
The main seeds of the first 4 classes include whole and damaged grains, as well as some broken or eaten ones. The nature and size of grain damage does not affect its relation to cultural or weed impurities. In class 5 wheat, the presence of leguminous seeds that are not included in the group of weeds is permissible.
The trash admixture includes:
- Mineral admixture: lumps of earth, pebbles;
- Plant particles, seeds;
- Darkened and empty wheat grains;
- Spores of smut, knot, ergot, etc .;
- Fusarium seeds.
The permissible percentage of trash for the first 4 classes is no more than 2. For the fifth class, no more than 5%. Prevents infestation of wheat by insects, except for mites (but not higher than the second degree). According to sanitary requirements, the presence of even a minimum amount of pesticides in wheat raw materials is unacceptable. Control was established for hexachporcyclohexane, DDT and their mebolites. For each batch, a certificate must be issued with a mandatory indication of the content of not only toxins, but also mycotoxins, pesticides. The permissible amount of pesticides according to GOST 13586.1: DDT metabolites - up to 0.05 mg / kg, HCH isomers - up to 0.2 mg / kg.
Storage and transportation
During transportation and storage, the condition of the cereal is taken into account:
- Humidity: dryness up to 14%, average dryness - up to 15.5%, wet - up to 17%, wet - over 17%;
- Weed impurity: pure grain - less than 1% of impurities, medium purity - up to 3% of impurity, over 3% - clogged grain.
During storage, it is necessary to provide wheat seeds with protection from pests - ticks, insects, mice, birds. For pest control, a set of physical and mechanical measures is used: heat treatment of raw materials, the use of chemicals, sound or mechanical traps. Pests of granaries, in accordance with sanitary standards, are detected by mechanical damage to grain, droppings, smell and other traces of vital activity. The damaged grain does not meet the standard and must be disposed of.
The quality of wheat depends on the chemical characteristics and type, affects the baking properties of flour and the subsequent taste of the finished product.
Determination of the composition of wheat seeds occurs in laboratory conditions using a special analysis. According to its results, the party is assigned to one of the classes. Acceptance rules and post-processing methods are regulated by federal law and are spelled out in the corresponding GOST.
The condition of wheat received for storage or processing must meet the standards: seeds must not contain harmful impurities and contamination with fungi and bacteria. Color, odor, weight and mass fraction of moisture must be within the permissible standard limits. If according to one of the criteria the grain does not meet the standard, the sample is sent for additional verification, based on the results of which a decision is made on disposal or admission to processing.
