What affects the color of the yolk and shell in chicken eggs. Egg shell color: what does it depend on

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What can tell the color of an egg yolk? Surely many of you choose eggs with a bright orange yolk on the market, right? Is it worth it? What kind of eggs really the most useful?

Read the whole truth about egg yolks!
Everyone knows, probably since childhood, that a fresh chicken egg is a storehouse of vitamins and microelements, very useful and delicious product. We were told that the brighter the color of the yolk, the healthier it is, right? Let's figure it out.

Which yolk in the photo do you consider the most useful, based on these statements?

The color of the egg yolk will change depending on the content of the chicken that laid it. This is no coincidence: the color of the yolk depends on the nutrients that the chicken eats.

Teno yellow yolk

Healthy, varied food, free-range chickens that eat not only grain, but also green mass, worms, bugs, and breathe fresh air, and, most importantly, get maximum sun - Better conditions that may contain chicken. These are home conditions. The yolk of such an egg is dark yellow, in the photo it is on the right.

The brighter the yolks, the more xanthophylls and omega-3 fatty acids, the large quantity vitamins A, D and E are found in the egg.

pale yolk

On the contrary, if these substances are absent or insufficient in eggs, and the egg has a pale yolk, then there is no benefit in the egg, and protein and fats can also be obtained from other products.

Farmers, poultry farms are interested in maximum profit, and therefore the attitude towards poultry is consumer: factory chickens “work” for wear and tear, do not see the sun and eat monotonous food, which at best consists of pure grain. These eggs are usually sold in supermarkets. This is the middle egg in the photo. These light yellow yolks are much less efficient at delivering nutrients to the body, meaning they are simply useless, though not harmful.

Bright orange yolk

The brightest egg, orange hue, and the most useful. Contrary to popular belief, the rich color of the yolk does not indicate an increased content of carotene, not all carotenoids can give color to the yolk. For example, the well-known beta-carotene is completely converted in the body of chickens into vitamin A and is consumed in metabolism. Therefore, beta-carotene does not affect the color of the yolk.

If the chicken is domesticated and receives grass, corn in the feed, and hay in winter, then her eggs will have a bright yellow yolk. If the chicken is factory-made, then the component of calendula, chamomile, nasturtium is added to the feed, which gives a bright orange tint, as in the photo on the left.

In the grocery department of the supermarket, we all have repeatedly paid attention to the different colors of chicken eggs - some chicken eggs are white, others are brown. Why are chicken eggs different color? So,

What determines the color of chicken eggs

The color of the shell of chicken eggs is determined by the pigment in the outer layer of the shell and it depends on the breed of the chicken that laid the egg. If the earlobe domestic chicken white color, then she carries white eggs, and if the lobe is red, then brown.

By the way, in South America there is a breed of chickens with feathered growths on the head, it is called "araucana". So, araucana hens lay blue eggs! Moreover, the Americans bred another chicken breed from this breed - "ameraucan". Ameraucana hens have peculiar "whiskers", and the color of their eggs can be yellow, green and even pink.

Egg yolk color

The color of the yolk of a chicken egg depends on the food that it is fed, or rather, on the pigments included in its composition. For example, a hen fed bright yellow varieties of corn, which contain an abundance of the yellow-orange pigment xanthophyll, will also have bright yellow egg yolks. And yellow alfalfa or varieties of corn with a pale yellow pigment, if fed mainly with them, will give a pale yellow color to the yolk of a chicken egg.

According to the publication "The Book of Facts"

Chicken eggs are white and brown. The opinion that brown is better in all respects is very common. So what determines the color of an egg in a chicken?

Depending on the breed of chickens, the shell can take on any shade from white to dark brown. But most birds lay white eggs. Chickens that lay brown eggs are less productive, and therefore of less interest to poultry farms. It is advisable to keep them only if the eggs can be sold for a higher price.

The color of the shell is associated with another particular problem. Eggs are translucent before being sold. By doing this, they try to detect unappetizing inclusions, such as blood stains, which can cause rejection in the buyer. With brown shells, blood inclusions are more difficult to detect than with white ones, and it is easier for such products to safely pass the pre-sale control and end up on the breakfast table.

The color of the shell does not at all determine the taste or quality features, and to the question why chicken eggs are of different colors, you can give 3 different answers. Color depends on:

• breeds;
• environmental conditions (air temperature, stressful situations, diseases of chickens);
• oviposition period.

When asked what determines the color of the yolk, experts gave the following answer.

Previously, when chickens were kept in more natural conditions, the yolk acquired a pale yellow color in winter and a golden yellow color in summer. The color of the egg yolk depends on the presence of carotenoids in the feed. Carotenoids are yellow and red hues found in corn, carrots and red peppers. The color of the yolk will not depend on the provitamin A, beta-carotene contained in carrots, but the pigments lutein and xanthophyll give the yolk a bright yellow color.

• In winter, chickens receive screenings, which are a mixture of weeds and waste that are formed during the cleaning of grain after grinding. This feed contains little carotene, and hens lay eggs with pale yolks.
• In summer, they independently search for food in green meadows, and the yolks are colored in golden yellow and red-brown, depending on what serves as food - greens or larvae of May beetles.

The perfect rustic egg contains light summer sun, although the color of the yolk is not an indicator of its naturalness, freshness or dietary value.

Currently, the color of the yolk no longer depends on the time of year.

Natural products have a significant drawback, namely: their components are not consistent in quantity and quality. Because of this, synthetic carotenoids are added to the feed for fidelity, and this leads to a constancy of the color of the yolk in summer and winter.

Last but not least, intuition is needed to formulate feed. The fact is that the desired golden yellow color of the yolk is obtained from the composition of red and yellow dyes.

The color of the yolk is a thing in itself: in addition to pigments, its color is also determined by other food components and factors:

• antioxidants added for stabilization;
• share of grain in feed;
• mold poisons;
• diseases of chickens;
• medicines used to treat chickens;
• conditions of detention (in daylight or in its absence).

All of the above are subject to various influences. And when you once again pick up an egg at breakfast, marvel at this natural wonder and the dexterity of its producers, and it will illuminate you sunlight yolk.

What color eggs are best?

At one of the agricultural exhibitions, a corresponding survey was carried out, and a third of the respondents preferred brown, a third - white, and the rest could not decide on their preferences. The consumer is inclined to believe that foods with intense color have a more pronounced taste.

What does the marking on chicken eggs mean?

According to Russian standards, the following marking is applied to the shell or to the packaging:

1. The first character is the letter D (dietary) painted in red or the letter C (table) painted in blue. Dietary eggs are considered only 7 days after being laid, then they go into the category of canteens.
2. The next character is a category, indicated by a number from 1 to 3 or by the letters O (selective) or B (highest category).

As an example, category 2 table eggs are labeled C2, with an average weight of 50 g. If an “egg” is indicated in a recipe for a culinary dish or a cosmetic mask, category 2 eggs are meant, although housewives sometimes refer to category 1 as “average”.

If desired, the manufacturer can apply the following (optional) signs:

• your trademark;
• the name of the poultry farm;
• expiration date with sorting date.

Are there two-color egg yolks, and why are they possible?

Answer. It happens that the manufacturer, in an effort to maintain the constancy of the color of the yolk in summer and winter, mixes carotenoids with chicken feed. With a sudden change in the composition of dyes, a two-color yolk is found in a boiled egg.

Does Eating Eggs Raise Cholesterol and Heart Attack Risk?

Answer. In a number of authoritative studies, no relationship has been found between the number of eggs eaten, blood cholesterol levels and mortality from cardiovascular diseases. An elderly man is known to have eaten 24 eggs daily for 15 years. His blood cholesterol level was below 5 mmol/l.

If the egg smells like fish, does that mean fishmeal was added to the chicken feed?

Certain breeds of hens lay smelly eggs when fed rapeseed, and this applies more to hens that lay brown eggs. Another undesirable taste imparts a large number of acorns, cockchafer larvae, onion, garlic husks, swede, cabbage, cottonseed, legumes, millet and rye, which are allowed to be used as feed in limited quantities and with preliminary heat treatment.

Answer. At one of the agricultural exhibitions, 3,000 visitors were offered hard-boiled eggs, and they were asked to indicate the most delicious ones. Processing of responses revealed that for the majority of visitors, eggs at the age of 14 days were considered the most delicious. The second place was taken by 3-day ones, and at the end of the list were 21-day ones.

How to determine if an egg is fresh or not?

Answer. It is most reliable to determine the age of eggs when they are broken: in fresh, the yolk is convex, limited by a dense shell, and two zones are clearly distinguished in the protein. In the old protein, it spreads widely, there are no zones in it, and the yolk is flat and soon bursts.

Where is contained more protein(protein), in white or yolk?

Answer. There are fewer proteins in the protein than in the yolk, the percentage content is 11 and 16%, respectively, that is, one and a half times more. Why then do bodybuilders prefer whites to yolks? Because there are no fats in the proteins, and in the yolks they are also 16%.

The color of the shell is determined by the breed of the chicken, and the color of the yolk is determined by the feed used to feed them in the last 2 weeks. The color of the shell does not affect consumer qualities, but by the color of the yolk and its consistency, you can determine the age of the egg, possible diseases of the hen and the conditions of its maintenance. The most valuable eggs of chickens kept in close to natural conditions who received complete food.

By the color of the egg yolk, you can determine the health of the chicken - it can be more or less intense yellow in color. But sometimes it happens that chickens begin to lay eggs with green yolks. Is this a deviation from the norm, is it possible to eat such products and what needs to be done to eliminate this problem - the answers to these questions in our article will be useful not only for poultry houses, but also for housewives who are faced with the task of choosing quality products.

What determines the color of the yolk

The color of an egg yolk depends on several factors, including:

1. Bird conditions. If the chicken is in household, walks in the wild and, in addition to absorbing grain, has the ability to row and find various bugs and worms in the ground, then the yolks of the eggs laid by it will be a more saturated yellow-orange color. But when the rules for keeping birds are violated, under which they are 24 hours a day in indoors, do not have the ability to move well and do not receive enough ultraviolet radiation, then the yolks of the testicles in such chickens will have a pale yellow color.
2. Seasonality. Sometimes the color of the yolks depends on seasonal changes: in winter it can be paler from less fresh vegetable feed and inadequate exposure to ultraviolet radiation.
3. Feed composition. If the chicken's body gets enough of everything nutrients and vitamins, then the yolks in the eggs will be painted in a more saturated color.

Important! Eggs with bright orange yolks are in high demand among the population, so unscrupulous manufacturers add artificial pigments to laying hen feed, which can adversely affect the health of consumers. Therefore, if the yolks of purchased eggs have an unnaturally bright color, it is better to refrain from purchasing them.

What color should egg yolks be?

Quality eggs from healthy laying hens may have yolks of varying shades of yellow, as this depends on the amount of carotenoids found in the food. These antioxidants contribute to the formation of vitamin A, which makes these foods valuable for our body.

Carotenoids are part of the following components of combined feeds:

• yellow;
• fruits;
• red paprika;
• green grass or substitutes (alfalfa grass meal).

Also, dark yolks indicate the content of fatty acids (Omega-3) and xanthophylls in them. If only grain predominates in the diet of the bird, then the egg yolks will be pale, with less nutritional value. Therefore, the better and better the bird's nutrition, the richer the color of the egg yolks, and the more valuable substances they contain.

Is it possible to eat eggs with green yolks

If you find that your chickens have started laying eggs with green content, or you have purchased such eggs from the store, then it is best to refrain from eating these products.

Did you know? If you cook scrambled eggs from one ostrich egg, then it will have the same volume as scrambled eggs from 25 chicken.

What to do if chickens began to lay eggs with a green yolk

First you need to trace whether all chickens began to give eggs with this pathology or only certain individuals. Then it is desirable to give such eggs for research.
To get an accurate conclusion about the causes of this phenomenon, it is best to contact the laboratory of veterinary and sanitary examination.

Reasons for rejection

Staining of yolks green tint may indicate the following factors:

1. Chickens are given food with green coloring pigments.
2. Viral diseases of chickens.
3. Old age laying hens.
4. Non-compliance with the storage conditions of eggs or damage to their shells, due to which harmful substances got inside.
5. Infection of eggs with putrefactive aerobic bacilli.

In the latter case, green rot occurs in the product, which is caused by various groups of Pseudomonas bacteria. These bacteria are usually found in traces chicken manure left on the egg shell.
With increased humidity from the surface of the shell, putrefactive bacilli penetrate freely into the egg and begin to multiply rapidly there, releasing greenish substances. Also, a green color may appear due to the development of Staph aureus bacilli inside.

How to bring the yolk back to normal

1. If it is established that the cause of the unnatural color of the yolk was the food, which included green color pigments, then it is advisable to review the diet of the brood hens and exclude such foods.
2. In case of viral diseases and other ailments, it is necessary to consult a veterinary specialist who will determine which virus the birds suffered from and prescribe them a course of a suitable antibiotic.
3. If the cause of the green yolk was the age of the laying hen, then this problem can be eliminated by the planned replacement of old individuals with younger ones.
4. It is important to observe the terms and conditions of storage of the product: in a dark, dry, cool place, at a constant temperature from 0 to +20°C, avoiding sudden temperature changes. Shelf life - 25 days.

Prevention of diseases affecting the color of the yolk

Here are some preventive measures to prevent the pathology in question in hens:

1. Vaccination. At the risk of spread viral diseases it is important to vaccinate birds regularly with a live attenuated vaccine, after which the vaccinated hens will have active immunity.
2. Rigid sanitation. To avoid viral diseases of hens, to prevent infection of eggs with putrefactive bacteria and microorganisms, as well as their spread inside the hen house, you must strictly adhere to the rules for collecting eggs, preserving them and the sanitary and hygienic requirements provided for in the preparation.
3. Correct conditions of detention. It is impossible to allow a large number of birds to be kept in a small area. The room where chickens are kept should be spacious enough and well ventilated.
4. Timely disposal of dead individuals. Dead birds should be burned or buried deep, sprinkled with quicklime.

Did you know? In the United States in 1910, a record was set for eating boiled eggs: a man ate 144 pieces at a time. To date, no one has been able to break this record, although attempts have been made repeatedly.

It is also important to remember that when poultry it is necessary to observe strict sanitary standards and a feeding regime, to give high-quality feed in order to exclude any anomalies and pathologies: both in pets and in the eggs they produce.

Many poultry farmers complain that their chickens lay eggs with pale yolks, like from a store. I note right away that the color does not depend on the color of the egg shell, the color of the plumage of chickens, the presence or absence of a rooster and others. folk signs". What is the reason?

The color of the egg yolk normally varies from golden yellow to yellow-orange. This color range is determined by certain pigments, and primarily carotenoids: lutein (found most in alfalfa) gives yellow color and zeaxanthin (found in corn) - orange-red.

The main factor that affects the color is the diet and the way the bird is kept. In the spring and summer, to get a bright egg yolk, it is enough to provide the bird with the opportunity to walk, that is, to allow plenty of “walking on the grass”. At the same time, stocks of vitamin feed for the winter should be made.

The greatest influence on the "beauty" of the yolk is the use of herbal flour. It is obtained by artificial drying of the green mass of alfalfa, clover and their mixtures with cereal herbs. Recall that legumes are mowed in the budding phase, and cereals - at the beginning of heading. In addition, alfalfa grass meal contains substances that favorably affect the growth of young animals and the productivity of poultry. True, getting high-quality herbal flour at home is quite problematic, since this requires exposure high temperature. Alternatively, you can dry the young plants out of direct sunlight. And it’s better if you get high-quality vitamin hay, because feeding it to adult laying hens in winter (up to 10 g per head per day) will have a very beneficial effect on egg yolks.

A good effect is also given by feeding corn to the bird, as well as nettle leaves rich in carotenoids (at home they can be dried, but only in the shade).

To obtain saturated color yolks, you can use carrots or pumpkins - up to 20 g per head per day. 1 kg of carrots contains 50-100 mg of carotenoids, and 1 kg of pumpkin contains 40-70 mg. In order to preserve vitamins, these vegetables can be ensiled (separately or mixed with other feeds when harvesting combined silage) or frozen (thawed in cold water before feeding).

There are also special synthetic pigments, but their use at home is undesirable for a number of reasons. Firstly, this is quite an expensive pleasure, secondly, the rate of their use is so small that it will cause difficulties when mixed with feed, and, finally, the most important thing is that all these drugs are obtained chemically.

Anatoly Romashko,

candidate of agricultural sciences,

head of nutrition departmentExperimental research station for poultry