1) find how many kilograms make up 45 servings 0.20x45=9 kg. 2) 1 kg of crumbly rice porridge contains 28 grams of salt. 28 gx9=252 g
table 3.32.
Since the yield of portions may be different, the addition of salt and spices is given approximately for column II, since the yield for the second column usually has an average yield mass between columns I and III.
As already mentioned above in the collection, the addition of salt and spices is not given, but it is necessary to include them when preparing and drawing up a technological map.
Example 19 . Let's add more conditions example 3 . To prepare borscht with cabbage and potatoes, in addition to the raw materials provided in recipe N 170, when determining the cost of the dish, you must not forget to add salt, spices and herbs. Besides, in brief description According to how borscht is prepared, it is indicated that it can be seasoned with sautéed flour diluted with broth or water (10 g of flour per 1000 g of borscht).
To prepare 1 kg of borscht you will also need the following products.
We find the losses for dill greens according to table No. 32 of the Appendix of the Collection to obtain 100 grams of dill, you need to spend 135 grams of gross weight. (it should be noted that losses of 26% in the Collection are given for dill supplied with roots). We find the gross amount to add to the borscht 135x3/100=4 grams Necessary spices and salt for borscht (see Table 3.33)
table 3.33
Determination of gross egg
As indicated in the collection of recipes, the recipes are based on the use of table chicken eggs of category II with an average weight of 46 g with waste for shells, stacks and losses of 12.5%. Therefore, the mass of raw and boiled eggs (without shell) is 40 g with a natural yolk to white ratio of 39 and 61%, respectively. However, eggs of other categories, that is, of greater or lesser weight, may be supplied for production. Therefore, it is necessary to recalculate the laying of eggs taking into account their actual mass using a conversion factor. Data with coefficients for recalculation in table 3.34.
table 3.34
The following formula is used for recalculation:
Gross mass of eggs in shell x K
Net weight of eggs without shell = – – – – – – – – – – -
In the formula TO– conversion factor from table 3.34
The actual weight of eggs is determined for each incoming batch, about which it is necessary to draw up a report in which the responsible persons indicate the invoice number, the name of the supplier, the number of eggs weighed, the average weight of one egg in the shell and without the shell.
Example 20 . Cafe "Paradise" received 1st category table eggs from the supplier. During control weighing, it turned out that the gross weight (in shell) of the eggs was 57 g,
In order for the eggs to be placed in technological map and subsequently calculate, it is necessary to determine what their net mass is. To do this, we will use the above table and formula. The net weight of a category 1 table egg without shell is 50 g (57 g x 88 / 100),
Recalculation of eggs is especially important for a confectionery shop, since the quality of the baked semi-finished product depends on the ratio of eggs and other components.
In the recipes of collections for the production of confectionery products, the laying of eggs is indicated in mass. Therefore, when an enterprise or a confectionery shop receives eggs with a weight different from the standard, it is necessary to recalculate what the consumption of eggs will be in pieces.
Example 10 The confectionery shop received eggs weighing 53 grams in shell. Determine the number of eggs to prepare 10 kilograms of sponge cake (main), if eggs weighing 53g in shell are used.
Let's find the mass of one egg without a shell using the conversion factor:
53x0.88 =46.64 grams
Let's round this mass to 47
To prepare 10 kilograms of sponge cake (main) you need: 5785.0 grams of eggs
If a confectionery shop uses eggs with a net weight of 47g, then to prepare a sponge cake you will need:
5785/47 = 123.085 eggs required to prepare 10 kg of biscuit (main) weighing 53g in shell.
The accountant makes all of the above calculations in order to indicate on the costing card the amount of raw materials and products according to gross standards required to prepare 100 servings of dishes or 10 kg of products. Costing cards will be discussed further.
Calculation of flour consumption taking into account its moisture content.
Flour products are divided into flour culinary and flour confectionery products. Flour culinary products include pancakes, pancakes, dumplings, belyashi pies and similar products. All of them are prepared from unleavened or yeast dough. Recipes for flour culinary products are contained in the collection of recipes for dishes and culinary products.
The same products as cakes, pastries and similar confectionery products are included in separate collections.
Collection of recipes for flour confectionery and bakery products 1986 edition;
Collection “Cakes, pastries, muffins, rolls”, 1978 edition.
The peculiarities of recipes for flour confectionery products for catering establishments are that the recipe is designed for 10 kg of finished product, and when producing cakes - for 100 pieces. At enterprises, working recipes are calculated to determine the consumption of raw materials and semi-finished products to produce the required number of products per shift. The working recipe can be designed for loading, taking into account the capacity of the equipment and its productivity.
The moisture content of flour is the most important indicator of its quality, according to which the amount of water for kneading dough is calculated. All calculations at enterprises are based on the basic moisture content of flour equal to 14.5%.
Recipes for flour culinary and flour confectionery products (cakes, pastries, muffins, rolls, pies, etc.) indicate the consumption of wheat flour with a basic moisture content of 14.5%.
When using wheat flour with a moisture content below 14.5%, its consumption is reduced by 1% for each percentage decrease in moisture content. At the same time, the consumption of liquid (water, milk) increases accordingly.
When using flour with a moisture content above 14.5%, its consumption increases, and the amount of liquid components provided for in the recipe decreases accordingly.
To make it easier to remember, the formula is as follows:
1% lower humidity – 1% less flour
More moisture by 1% - more flour by 1%
Example 21. Let's calculate the amount of flour for the production of 200 donuts according to recipe No. 1056 of the Collection, if the flour arrived with a moisture content of 12.5%
Recipe according to the collection in Table 3.35:
table 3.35
To prepare 200 pcs. donuts No. 1056, the consumption of wheat flour with a basic moisture content of 14.5% should be 5300 grams. And the flour received by the enterprise has a moisture content of 12.5%. This means that you need to take 2% less flour to make donuts.
Let's calculate the consumption for flour with the received moisture indicators.
5300-5300x2/100=5194
That is, flour consumption decreased by 106 grams, accordingly, water consumption should be increased by 106 grams.
Determination of freshness and quality indicators
eggs of various batches
Eggs have high biological value, which is characterized by a high protein content, essential amino acids, fats, vitamins, minerals.
Only good-quality eggs from chickens, ducks, geese, turkeys, and guinea fowl are used for food purposes. Egg processing plants process only chicken eggs. Turkey, guinea fowl, and quail eggs are not used due to limited production volumes; goose and duck eggs are used after neutralization treatment.
Egg processing plants receive eggs from poultry farms in sorted form. When sorting eggs into categories, they are assessed by weight, shell condition, condition of the air chamber and its height, condition of the yolk and white.
Dietary and table eggs of categories I and II are supplied for processing. It is allowed to use eggs with contaminated shells and small eggs (eggs weighing less than 40-43 g).
Dietary eggs include eggs that have been laid for no more than 7 days and whose weight is at least 40-44 g.
Table eggs include eggs that have been laid for more than 7 days, as well as eggs with a shorter shelf life weighing less than 40-44 g.
The weight of a dietary category I egg must be at least 54 g, category II at least 44 g; the weight of one table egg of category I is not less than 48 g, category II is not less than 43 g.
The poultry processing industry produces frozen egg products (melange, white and yolk), dried egg products, fermented (desugared). The process of producing egg products can be carried out either manually or mechanized. Moreover, at the initial stages, sanitary treatment of eggs is carried out in the same way, which includes washing, drying, and disinfection.
When processing eggs with clean shells, their sanitary processing does not present significant difficulties and can be easily mechanized. When washing contaminated eggs, pre-soak them.
In the production of egg products, control is carried out over the storage of raw materials, sorting, washing, disinfection and breaking of eggs, their contents, filtration and mixing of the egg mass, pasteurization and cooling, as well as packaging, packaging, drying of products and acceptance of containers.
A conclusion about the quality of a product and its nutritional value is drawn up on the basis of physicochemical, bacteriological indicators and organoleptic characteristics.
When sorting eggs using the ovoscopic method, the strength of the shell, the condition and size of the air chamber are taken into account. The safety of eggs during collection and transportation depends on the strength of the shell, which indicates the level of mineral metabolism in the hen’s body. The strength of the shell is determined in several ways: by measuring the thickness of the shell, determining the specific gravity of the egg, as well as the resistance of the eggs to crushing.
The change in the density of the yolk and white, as well as the egg as a whole, depends on the evaporation of moisture through the pores of the shell. The amount of shrinkage during egg storage is significant. During long-term storage, especially at high temperatures, the egg can dry out almost to equilibrium moisture content. Thus, a change in the density of the egg contents during storage can be considered a characteristic sign of its “aging”.
Indicators of egg quality are also the protein and yolk indices, the ratio of components, which vary significantly depending on the conditions and duration of storage.
The purpose of the work is to determine the mass, category and quality indicators of eggs: shell strength, white and yolk index, ratio of components and their density.
The work is carried out by a group of students of 3-4 people who determine the quality indicators of eggs from different batches and different shelf life.
Raw materials, equipment, utensils, reagents:
chicken eggs, sodium chloride, technical scales, analytical balances, micrometer with pointed rods (accuracy up to 0.01 mm) or lever micrometer (division value 0.002 mm) or indicator micrometer, tweezers, hydrometer (division value 0.05 g/cm 3 ), altimeter (micrometer vertically mounted on a tripod), calipers, pycnometer, pointed scissors with curved ends, glass measuring 30x30 cm, egg stand, cup for collecting shells, dishes for draining egg contents, glass rod, beakers, pipettes, thermometer , alcohol, water, cotton wool, filter paper, graph paper
Progress
1 . Determination of egg quality
Previously, the quality of eggs is determined visually using an ovoscope. Benign eggs do not have visible foreign inclusions. Broken eggs are discarded. The mass of eggs is determined by group weighing on technical scales.
2. Determination of egg shell thickness
Shell thickness varies in different areas and among laying hens different types and breeds. It is determined using micrometers of various designs.
2.1. Remove the contents of the egg, wash the inner surface warm water and dried with filter paper. Small pieces are broken off alternately from the equatorial part of the blunt and sharp ends of the shell and the subshell membrane is removed with tweezers (without teeth). A piece of shell is clamped with the rods of a micrometer, the movable drum of which is rotated until the arrow on the control scale reaches zero. Then the readings are taken on the longitudinal and circular scales.
2.2. To determine the thickness, an indicator micrometer is used, which is a dial-type indicator mounted on a stable stand.
The shell is placed on a stationary stand, the movable rod is lowered until it comes into contact with the shell. The reading is made on a micrometer scale.
The thickness of a piece of each section of the shell is measured at least three times, then the average value is calculated (in mm).
2.3. Methodology Yu.N. Vladimirova is based on the fact that there is a direct relationship between the specific gravity of a fresh egg (1.085-1.090 kg/m3) and the thickness of the shell. When immersing eggs in an aqueous solution table salt At a certain concentration, some eggs float to the surface, while others sink to the bottom of the vessel. Consequently, the shells of floating eggs are thinner than those of sunken eggs.
To study fresh eggs, prepare 8-10 solutions of varying concentrations (from 1.065 to 1.100 g/cm 3 with an interval of 0.005). Each of them is poured into a separate vessel, on which its density is indicated. The concentration is periodically checked and salt or water is added if necessary.
The egg is immersed in a solution of the lowest density. If it sinks to the bottom, it is successively moved from one solution of lower density to another, higher, until it is suspended. This means that the specific gravity of the egg corresponds to the density of the solution.
3.Measurement of shell strength
The strength of the shell is determined by crushing and measuring the pressure that the egg can withstand when compressed (for chicken eggs it averages 4.5-4.2 kg).
The eggs are placed in the cup-shaped nest of the device. When the pressure nut is slowly rotated, the egg with the socket smoothly rises, comes into contact with the surface of the disk located parallel to the socket, and is clamped by it. When a cracking sound occurs, signaling the destruction of the shell, the rotation of the nut is stopped. In this case, the retarded arrow indicates the maximum value of the load achieved, equal to the tensile strength of the shell.
4.Determination of protein and yolk indices
The protein index is characterized by the ratio of the height of the outer layer of dense protein to the average diameter of this layer, and the yolk index by the ratio of its height to width. In fresh eggs, the average protein index is 0.075-0.085, yolk – 0.40-0.45. As the storage period increases, the indices decrease.
The altimeter is preliminarily set so that when its rod comes into contact with the glass, the risk of the moving drum is at zero. If the micrometer is tightly connected to the tripod, then find the zero point and record the first reading.
After setting the altimeter, begin opening the egg. To do this, it is placed in a horizontal position on a special stand and an oval hole 3-4 cm long is cut out with pointed scissors. In order not to damage the protein layer and the yolk membrane, the scissors are inserted under the shell at an acute angle no more than 2-3 cm. Then the contents of the egg pour onto a horizontal glass and carefully place it under the micrometer rod, which must be raised. It is better to place the glass on the table so that it is at eye level.
To measure the height of the yolk, the micrometer rod is lowered until it comes into contact with the surface of its central part, determining this moment by the change in tension on the surface of the yolk. Then measure the height of the dense protein layer along its long axis, which is equal to half the distance of this layer from the yolk.
The diameters of the white and yolk are determined using calipers. The longitudinal and transverse diameters of the yolk are measured, and the small and large diameters of the white. The average diameters of the yolk and outer firm white are obtained by dividing the sum of the two diameters.
The yolk or white indices are equal to the ratio of height to average diameter and are determined by the formula
TO= ,
Where h- height, m;
D- large (longitudinal) diameter, m;
d- small (transverse) diameter, m.
5. Determination of the ratio of egg components
The egg is weighed to the nearest 0.1 g, then an oval hole with a diameter of 3-4 cm is cut out with scissors at the blunt end of the shell. The contents of the egg are carefully poured onto a watch glass, the remaining protein is sucked off with a pipette. The cut portion of the shell and the rebound pieces are placed in the shell and everything is weighed.
The protein layers are separated as follows: first, using a pipette with a hole diameter of 1 mm, the outer liquid soybean is sucked out and placed in a bottle with a ground-in lid (the bottles must first be weighed and numbered). After removing the outer layer of the protein in two or three places, use scissors to trim the middle dense layer of the protein (in order not to damage the yolk, the sharp ends of the scissors should be facing in the opposite direction from it). In this case, the inner liquid protein flows out of the protein sac, which is sucked off with the same pipette as the outer one, and placed in the next bottle. Using a pipette with a hole diameter of 2 mm, a dense layer of protein is sucked out, after which the inner dense (chaladze) layer of protein is removed from the yolk with a brush or a chicken feather, grabbed with tweezers and placed in a weighing bottle. The hailstones (khaladzy) are carefully separated from the yolk with scissors and transferred to the same bottle with tweezers. The yolk, freed from the white, is placed in the fifth bottle. All layers of white and yolk are weighed to the nearest 0.01 g.
If it is necessary to separate the white, yolk and shell, then after the contents of the egg are poured onto a watch glass, the dense white is cut in several places, then the entire white is carefully poured into the vessel, holding the yolk with a glass rod. The remaining protein is sucked off with a pipette. In this case, only the yolk and shell are weighed. The mass of the protein is determined by subtracting the mass of the yolk and shell from the mass of the egg.
Mass of protein, yolk and shell ( X) are expressed as a percentage of the mass of the egg, the mass of individual layers of protein ( X 1) – as a percentage of the total protein mass according to the formulas
X = ,
X 1= ,
Where n– mass of protein (yolk or shell), g;
M– egg mass, g;
m 1– mass of one protein layer, g;
b– total protein mass, g.
The protein to yolk ratio is defined as the ratio of the mass of the white to the mass of the yolk (in g).
Depending on the quality, eggs are divided into edible, incomplete edible and technical defective.
Food grade includes fresh, benign eggs with a clean shell, without mechanical damage, with an air chamber height of no more than 13 mm; with dense, translucent, viscous protein; with a clean, viscous yolk, uniformly colored yellow or orange.
Food eggs are divided into dietary and table eggs. Eggs that have been stored for no more than 7 days, not counting the day of laying, are considered dietary. After the expiration of this period, they are transferred to canteens according to the act.
Table eggs include eggs whose shelf life does not exceed 25 days from the date of sorting, not counting the day of laying, and eggs stored in refrigerators for no more than 120 days. Eggs are sorted no later than one day after laying.
Depending on the weight, eggs are divided into 3 categories: selected - at least 65 g; Category I – not less than 55 g; Category II – at least 45 g. Eggs weighing less than 45 g cannot be sold in retail chains. They are defined as small and sent for industrial processing.
Main indicators of egg quality: weight; cleanliness and integrity of the shell; condition and size of the air chamber; consistency of internal egg fractions; position and mobility of the yolk. They are used during delivery and acceptance.
In production food eggs The integrity of the shell is of particular importance. The shells of diet and table eggs must be clean and undamaged. On the shell of dietary eggs, the presence of single dots or stripes is allowed, and on the shell of table eggs - spots, dots and stripes (traces from the contact of the egg with the floor of the cage or a conveyor for processing eggs) of no more than 1/8 of its surface. Egg shells should be free of blood stains and droppings.
Shell strength can be determined by measuring its thickness, density, and crush resistance.
Based on the condition of the air chamber, yolk and white, eggs must meet the following requirements:
Dietary - the air chamber is stationary, height no more than 4 mm. The protein is dense, light, transparent. The yolk is strong, barely visible, but the contours are not visible, occupies a central position and does not move;
Dining rooms - the air chamber is fixed (some mobility is allowed), the height is no more than 7 mm, and for eggs stored in refrigerators - no more than 9 mm. The white is dense (not dense enough is allowed), the yolk is inconspicuous, may move slightly, and there may be a slight deviation from the central position. In eggs stored in the refrigerator, the yolk moves.
The contents of food eggs should not have any foreign odors. The requirements for food eggs are given in Table 10.
10. Requirements for the quality of edible eggs
|
Indicators |
Characteristic |
|
Egg mass |
In accordance with the current specifications |
|
Shell |
Clean, undamaged, for canteens minor contamination in the form of isolated spots is allowed |
|
Air chamber |
Fixed, height no more than 4 mm for dietary, no more than 7 and 9 mm for canteens |
|
Dense, poorly defined contours, occupies a central position, inactive; for table eggs slightly moving, weakened |
|
|
Dense, translucent, for table eggs weak, watery is allowed |
|
|
Additional requirements |
|
|
Density of eggs, g/cm3 |
Not less than 1.075 |
|
Shell: appearance marbling strength, kgf (N) elastic deformation, µm thickness, µm relative mass, % |
Smooth, without growths, sagging, roughness Absent or insignificant Not less than 3.1 (30.4) No more than 25 Not less than 320 At least 9 |
|
Egg shape: appearance shape index, % white to yolk ratio protein index, % Howe units yolk index yolk pigmentation, score |
asymmetrical ellipse with well-defined sharp and obtuse poles. no more than 2 at least 7 not less than 80 at least 40 |
|
not less than 12.0 not less than 50.0 |
|
|
carotenoids, mcg retinol, mcg |
at least 15 at least 6 |
|
Egg smell |
absent |
|
Taste of boiled or fried egg |
pleasant, characteristic |
|
Boiled or fried egg aroma |
strong, pleasant |
Food eggs that have various types of defects are divided into defective, or food waste, and unsuitable for food, or technical defects.
Eggs with the following defects are classified as food defects:
The height of the air chamber is more than 13 mm. The formation of an air chamber (puga) begins immediately after the egg is laid due to the difference in the temperature of the chicken’s body and the surrounding air. The height of the puga (the distance from its center to the shell) of newly laid eggs is 0.10-0.35 mm, after 4-7 days of storage under normal conditions - 2-3 mm, after 1 month - 11-13 mm. The height of the puga is determined by scanning the eggs using an ovoscope. This indicator serves as a characteristic sign of the freshness of eggs.
- “battle” - eggs with a damaged shell without signs of leakage (“notch”, “crumpled side”) and “leaking”. “Crack” means the presence of subtle cracks in the shell, which can be easily detected when viewing eggs on an ovoscope or by tapping eggs on eggs. “Crumpled side” - more significant damage to the shell. In both cases, the under-shell films remain intact, so there are no signs of leakage. Damage to the subshell membranes is accompanied by “lek”. The reason for this defect is a violation of the rules for handling eggs during collection, packaging, transportation and sorting.
- “pouring” - can be small or large. “Small pouring” is characterized by partial mixing of the yolk with the white. When the vitelline membrane is ruptured, the yolk has an irregular shape. Sometimes dark streaks are visible in the white. The white is liquid, unevenly dotted with yolk mass. “Big pouring” is also formed as a result of the rupture of the yolk membrane and is characterized by complete mixing of the white and yolk, due to which the egg acquires a yellowish color.
- “small spot” - eggs with one or more fixed spots under the shell with a total size of no more than 1/8 of the surface of the shell. The defect occurs when mold fungi penetrate under the shell and form mold colonies of various colors on the under-shell films. Eggs with small spots can be used for food, but their further storage will lead to the appearance of more undesirable defects - a “big spot” or a “moldy cuff.”
- “dry” - eggs with the yolk dried to the shell, but without mold. This is due to the liquefaction of the protein, which is accompanied by a weakening of the hailstones. The latter lose the ability to hold the yolk in the center of the egg, and it floats, since the specific gravity of the yolk is less than that of the white.
Pumping" - is formed when the tunica albuginea ruptures in the area of the air chamber. The air passes under the film, as a result the air chamber seems to move depending on the position of the egg. These eggs must be immediately used for food purposes, since they cannot be stored even for short-term storage.
- “smelly” - eggs with a foreign odor acquired as a result of storage indoors together with odorous substances or materials.
Food-grade eggs are sent for industrial processing.
Eggs with the following defects are considered technical defects:
- “cuff” - eggs with dark, opaque contents, which indicates the development of microbes and fungi. Often, when opened, such eggs have bad smell, and the white and yolk are discolored.
- “krasyuk” - this defect occurs when the yolk membrane is completely destroyed and the white and yolk are mixed. Formed during aging of eggs and during prolonged storage in inappropriate conditions. The aging of eggs is accompanied by the loss of water and the movement of some of it into the yolk due to the fact that the vitelline membrane becomes more permeable and less elastic. The yolk expands and becomes flat, the shell breaks and the white mixes with the yolk.
- “blood ring” - eggs on the surface of the yolk of which blood vessels are visible in the form of a ring, sometimes covering the entire perimeter of the egg. This defect often manifests itself when fertilized eggs are stored in conditions high temperature(21 C and above), which leads to the beginning of the development of the embryo and its subsequent death.
- “large spot” - eggs with one or more fixed spots under the shell, with a total size of more than 1/8 of the surface of the shell.
- “mirage” - eggs removed from the incubator after the first viewing as unfertilized.
Eggs with “cuff” contents are destroyed on the spot, and those with other defects are sent for processing into feed flour.
Self-test questions:
1.Which eggs are considered dietary and which are table eggs?
2.List the requirements for dietary and table eggs.
4.Describe the requirements for the quality of edible eggs.
5.What defects reduce the quality of edible eggs?
6.What defects in eggs can be classified as incomplete food and how
are they used?
7.Tell me which eggs are classified as technical defects?
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Introduction
The purpose of our work is to determine the strength of a chicken egg (with different shell colors: white and brown), for which physical methods were used and chemical experiments were carried out.
1. Study the literature on the research topic.
2. Study the structure of the egg shell.
3. Learn to determine the mass, density, strength of eggs.
The relevance of this topic is that it reveals approaches to solving practical problems that arise in everyday life. Chicken eggs are nutritious and healthy food. Biologically complete egg protein in its composition approaches the optimal requirement of the human body for amino acids. Bread and milk, eggs and meat, vegetables and fish are traditional food products for Russians. And eggs have been part of natural food throughout human history.
Today nutritionists recommend healthy person eat 1-2 eggs a day. One chicken egg satisfies the daily requirement of an adult for protein by 10%, fat - 7%, phospholipids (lecithin) - more than 50%, vitamins - from 5 to 100%, iodine - 1 5-20%, zinc and copper - 8-1 0%, selenium - up to 50%.
Among the characteristic criteria for egg quality, weight comes first; the larger the egg, the higher its nutritional value. The weight of eggs varies widely, but most often from 45 to 65 g.
Strength is the main quality of egg shells. The shell is a calcareous shell, which consists of two layers: the inner, which makes up one third of the shell, and the outer. Its thickness is 0.2-0.4 mm with a decrease at the blunt end. The shell protects the contents of the egg from mechanical damage, microbial contamination and moisture evaporation. Egg shells contain calcium carbonate (93.5%) and magnesium (1.4%), calcium and magnesium phosphates (0.8%), and a small amount of organic substances.
The color of the shell depends on the type and breed of bird. In chickens of egg breeds it is white, in chickens of meat it has various shades - from straw yellow to brown. In this work we will find out whether color affects the strength of the shell.
Research hypothesis:
The color of the eggs affects the strength of the shell;
An egg with a brown shell is more durable because... contains more calcium carbonate than a white-shelled egg.
Location of the study: the city of Izhevsk.
Object of study: chicken eggs.
Breeds of chickens and their modern distribution
Edible eggs are obtained mainly from egg-laying chickens, and to a lesser extent from meat - egg-laying and meat chickens. The main source of poultry meat is broiler farming. Modern poultry farms are full-fledged production facilities engaged in both growing poultry and producing semi-finished products from its meat. The main processes are automated. A battery cage is most often used to keep birds.
The main characteristics that form the basis for the classification of breeds include the direction of their use by humans, live weight, egg production, plumage color, comb shape, size and color of eggs, safety of young and adult birds, etc.
All breeds are divided into the following main groups according to their use:
broilers (have low egg production, but high body weight and taste)
laying hens (have high egg production, but often low taste, sometimes low body weight),
meat - egg (as a rule, they have medium egg production and medium or high body weight, as well as good taste),
fighting (individuals are massive, elongated, the direction is created for cockfighting),
decorative (have unusual decorative properties - dwarfism, special colors, etc.).
In accordance with this classification, all breeds of chickens can be grouped as follows:
meat chickens - Brama, Cochin, etc.
egg hens - Leghorn, Russian White, Rhodonite-2, etc.
meat and egg chickens - Orpington, Faverolles, Wyandotte, Australorp, Amrox, Kuchin Jubilee, Moscow White, Moscow, New Hampshire, Rhode Island, etc.
fighting chickens - Azil, English fighting, Indian black, Malayan, Moscow fighting, etc.
ornamental chickens - Seabright, bantam, dwarf Wyandotte, Dutch black white-crested, dwarf Cochin, curly-haired, paduan, silky, etc.
Have you ever wondered what determines the color of a chicken's eggs? After all, there are shells of different colors, both white and brown. What are these - different types of eggs or a sign of quality? Let's try to figure out what affects the pigmentation of the shell and yolk.
Among ordinary people there is an opinion that the composition of eggs Brown more natural, so to speak, homemade. In fact, the quality of the product produced by a laying hen depends on many factors. But the color does not in any way affect the taste or quality of the eggs. Conversely, the conditions of keeping and feeding the chicken do not in any way affect the color of the food prepared from it. And yet, what does it depend on? different colour chicken eggs?
Factor 1. Breed
So, the color of the shell in the products laid by domestic and industrial chickens depends on the breed of bird. At the same time, the ability to lay eggs of a certain color is determined genetically. That is, the same chicken throughout its entire life produces fruits with a shell of a certain color. And the following pattern is often observed: the color of the shell depends on the color of the feathers.
Thus, laying hens with white feathers mainly lay white, but those with pockmarked and golden feathers lay brown. To know for sure what color your chicken's eggs will be, take a closer look at her earlobe. If it is white, then the eggs will have the same color. Chickens with red lobes will have a brown shell color.
Each breed of chicken has certain color characteristics. So, Leghorns and Russian Whites have plumage white, and their shells are the same color. By the way, these breeds are distinguished by the highest egg production. That is why in shops and markets it prevails protein product with a white shell.
IN household They prefer to have birds that can lay eggs and confidently gain weight. Such breeds are mostly brown in color, and accordingly their eggs acquire the same color. These include Dominican laying hens, Rhode Island, Orpington and other meat and egg chickens.
For some reason, people have the opinion that since domestic eggs have a brown tint, this is a sign of their naturalness. One way or another, this stereotype is based on the subconscious and has nothing to do with common sense. But farmers are developing new breeds that lay eggs well and produce brown eggs to win the favor of buyers.
By the way, we are all used to seeing chicken products with white and brown shells on our table. And in South America there is a specific breed of chicken that lays bluish-green eggs. The chickens themselves look very original: they have no tails, but feather decorations have formed on their heads in the form of mustaches and beards. The breed is called “Araucana” - in honor of the name of the Indian tribe that bred such chickens.
In the middle of the last century, eggs from Araucanian chickens gained popularity, but why? Among Americans, an opinion has emerged that the protein product of these strange birds contains several times more useful substances, and the cholesterol level, on the contrary, is significantly lower than in ordinary eggs. However, later studies showed that the chemical composition of such eggs is no different from others, and the hype passed.
Factor 2. Environmental conditions
The color intensity of the shell varies from pale, creamy shades to rich reddish ones. What does this depend on? The color of the shell is influenced by various external factors: air temperature, stressful situations, diseases. The brownish tint is produced by a pigment called protoporphyrin. It is found in hemoglobin and various vitamins, and is quite common in many forms of living nature.
The more time it takes for the fetus to pass through the oviduct, the more intensely it is colored. This happens because porphyrin acts on the shell longer. Also, the intensity of the color depends on the period of oviposition: the first ones usually turn out darker.
Scientific research has proven that the color pigment that influences the formation of color is located in the cells of the uterine organ of the laying hen. Therefore, the color of the shell is determined even at the initial stages of egg formation.
What affects the color of the yolk?
Color egg yolk sometimes worries both beginners and experienced housewives. Let's figure out why the yolks in one egg are pale yellow, in another they have a bright, rich hue, and in the third there may even be a poisonous orange yolk.
The color of the yolk is a consequence of the influence of pigments belonging to the group of carotenoids. Carotenoids are natural pigments and give color to plants and fruits. However, not all types of pigment affect the color of the yolk. For example, beta-carotene, which makes carrots orange, will not affect the color of the yolk. But the pigments lutein or xanthophyll can achieve the bright color of egg yolk.
The color of the yolk depends on the bird's diet. If the chicken eats foods rich in yellow pigment, the yolk will have a deeper yellow or orange hue. This effect is achieved by bright yellow corn and grass meal. If you feed chickens with pale varieties of corn and alfalfa, the color of the yolk will be pale yellow. When feeding with colorless food, the yolk will have a barely noticeable yellow tint.
This indicator does not indicate the freshness, naturalness or nutritional value of the egg product. But producers of eggs for sale try to feed laying hens with brightly colored feed to make the product look more attractive to the buyer. Interesting fact: for some reason the yolk contains more protein than the protein itself, so the benefits of the yolk are not measured by the shade.
Research methodology
The mass fraction of the shell is an indirect indicator of its thickness and strength. To determine this indicator, the egg and shell (without the under-shell film) are weighed with an accuracy of 0.1 g, and then the ratio (in%) is calculated using the formula, where is a dimensionless quantity equal to the ratio of the mass of the shell to the mass of the egg (we took this formula from chemistry textbook for 8th grade).
2. Shell strength is the most important indicator of an egg. The shell is crushed until a crack appears.
Take raw eggs, carefully drill holes in the ends (using a needle) and pour the contents of the eggs out through them. We glue adhesive tape to the side surface of each egg so that it runs along its equator, dividing the egg into two hemispheres - with blunt and sharp ends. Duct tape is needed so that the hemispheres do not crack when we separate them from one another. Then you need to take a scalpel and cut the empty eggs along the middle line of the adhesive tape. You will get empty egg hemispheres. Place them on a flat table surface with the poles up (cut edges down) so that they form a square with a side of 15 cm.
Now let’s carefully place the weights. The data obtained was entered into table 1. Then they found the mass that the egg can withstand in a horizontal position, which will make it possible to find out which egg is stronger.
3. Composition of calcium carbonate in the shell. To do this, we need an egg with a brown and white shell, acetic acid and a glass cup (so that the egg can fit in it).
Place the egg in a glass and fill the glass with vinegar (9%). We leave the entire composition in this form for several days.
The calcium carbonate found in the egg shell must react with acetic acid to form a solution of calcium acetate, and the white and yolk are denatured (changed the shape of the protein molecules) under the influence of an acidic environment. We will observe the changes occurring with the shell (brown, white), which shell will dissolve faster.
4. Determination of the density of an irregularly shaped body (chicken egg).
Density is determined by the formula, ρ=m/V, which we studied in 7th grade in physics lessons. The mass can be determined by weighing on a scale, and the volume can be found as the difference between the volume of water in a beaker with and without an egg.
The volume is calculated using the formula V eggs = V (water with egg) - V (water).
Density is determined by the formula ρ=m/V.
4. Research results and their analysis
1. The mass fraction of the shell is an indirect indicator of its thickness and strength.
To calculate the mass fraction of the shell, we took one egg, weighed it on a scale, and got the following result: an egg with a white shell 55 g, with a brown shell - 49 g. Next, we broke it and poured the contents into a cup. The shell was weighed and it was found that the weight of the white shell was 6 g, and that of the brown shell was 7 g.
We carried out the calculation:
For white shell eggs: 6 grams is 11% of the total weight of the egg.
For eggs with brown shells: 6 grams is 12% of the total weight of the egg.
The mass fraction of brown shells is greater than the mass fraction of white shells.
2. The results of determining the strength of eggs with brown and white shells were entered into the table.
Table 1. Determination of egg shell strength.
The brown shell withstood a mass of weights of 1 kg 500 g and was crushed, which is 220 g more than the white shell withstood.
3. The laying was carried out on January 5 at 13.40 hours. After 19 hours, the egg shells were examined, changes occurring with the shells (brown, white) in vinegar were observed, which shells dissolved faster. Brown shells dissolved completely after 27 hours, while white shells dissolved after 23 hours. This experience proves our hypothesis that an egg with a brown shell is stronger because... contains more calcium carbonate than a white-shelled egg.
4. To determine density, you need to divide the mass by the volume. The mass can be determined by weighing on a scale, and the volume can be found as the difference between the volume of water in a beaker with and without an egg.
Table 2. Determination of egg density.
The volume was calculated using the formula (water)
Density was determined using the formula
5. Conclusions:
1. The larger the chicken eggs, the weaker their shells.
2. Brown chicken eggs are much stronger than those with white shells. Brown eggs have slightly thicker shells, so they have a slightly longer shelf life. They are less susceptible to damage.
3. The thickness of the shell is related to the density of the eggs. The thicker the shell, the denser the egg.
5. Eggs are healthy and nutritious. On average, a chicken egg contains 80 kilocalories. In terms of calorie content, it is equivalent to a medium-sized apple, half a banana, 100 grams of beef tongue or chicken legs. In addition, eggs contain valuable vitamins, microelements and protein. Eating eggs not only provides energy, but also has a positive effect on the condition of hair, vision and the entire body.
6. Cholesterol in eggs is not as dangerous as is commonly believed - it is found only in the yolk and is balanced by lecithin (a substance also found in eggs that helps process cholesterol and fats).
7. Eating raw eggs is dangerous. Delicious eggnog can bring unpleasant consequences in the form of salmonellosis. The dangerous bacterium is often found in raw eggs and is killed when cooked. It is also important to wash the eggs thoroughly and prevent germs from the surface of the shell from entering the egg mass.
8. On average, a laying hen produces approximately 250 - 300 eggs per year. It takes her about a day to lay one egg.
9. White eggs are just as healthy as brown ones. Contrary to the widespread myth about the exceptional benefits and taste of brown eggs in comparison with white ones, the latter are no worse. The only difference is the breed of chickens that lay these same eggs. The color of the shell depends on the color of the hen - speckled hens have brown and beige eggs, and white hens lay white eggs. The color of the yolk depends only on the chicken's diet.
10. Diet eggs are healthier than table eggs. The classification of eggs into dietary and table eggs depends on their freshness. Eggs stored at positive temperatures for no more than 7 days after laying are considered dietary. Canteens can be stored for up to 25 days. Dietary, in turn, are divided into selected (from 65 grams) and eggs I (at least 55 grams) and II (at least 45 grams) categories.
11. Eggs should not be stored next to strong-smelling foods. Thanks to their porous shells, they easily absorb odors.
12. The longer the egg was exposed heat treatment, the harder it is to digest. A hard-boiled egg will be digested by the body in about three hours. That is why it is better not to eat hard-boiled eggs before bed.
6. Conclusion
In what follows we assume that will be investigated:
1. Is cholesterol in eggs as dangerous as is commonly believed or is it contained only in the yolk and is balanced by lecithin (a substance also found in eggs that helps process cholesterol and fats).
2. Is it possible to store eggs next to strong-smelling foods? Thanks to their porous shells, they easily absorb odors.
3. How to determine the freshness of an egg? Is it true or myth that you can put it in a bowl of cold water. The fresher the egg, the smaller its air chamber, which means the egg will sink. At the same time, a stale egg will float to the surface; such an egg is not advisable to eat.
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