Views: 2023 Author: LONGMU Publish Time: 2023-07-19 Origin: LONGMU
Eggs are definitely the most amazing existence in human kitchens. People are so familiar with them that they almost turn a blind eye. There is really no food that is as simple and nutritious as eggs and can conjure up such a variety of dishes.
But there are still many questions about eggs that many people don't know: How many eggs can you eat every day? Are free-range eggs better? Eggs with darker shells are more nutritious? Have you ever had such a question? Let's answer them one by one.
Q1: How many eggs can you eat every day?
A: I always hear people say that eggs are high in cholesterol, so you can only eat two at most a day. But in fact, judging from existing research, eating two or more eggs a day does not lead to an increased risk of cardiovascular disease or diabetes. At present, it is agreed at home and abroad that the amount of cholesterol in food does not have much impact on the amount of cholesterol in the body and cardiovascular diseases. Many countries have canceled the restrictions on cholesterol.
But from the perspective of a balanced diet, it is recommended that you eat a variety of foods, and it is not recommended to eat too much of any food.
In the case of a normal intake of other foods (milk, meat, fish, and shrimp), do not eat more than 7 eggs a week. Of course, if the intake of milk, meat, fish, and shrimp in the diet is insufficient, or if you are exercising and need to supplement protein, or you like to eat eggs, you don’t have to worry about any problems if you eat more eggs.
Q2: Are dark eggs better?
A: Eggs come in a variety of colors, and the color has nothing to do with nutrition. Eggshells are mainly composed of calcium carbonate, calcium phosphate, and a small amount of protein. If there is no pigment involved, the eggs are originally white. The laying hens that produce white eggs include Leghorn and silky chickens; some hens secrete A special kind of mucus not only has lubricating and antibacterial effects but also contains a pink pigment, which makes the white eggs pink.
Some chickens can produce blue eggs, which come from the biliverdin in chicken bile, such as Araucana chickens in the Americas, Easter hens, etc.; some chickens can produce chocolate-colored eggs, which come from A pigment called "protoporphyrin", such as Mylan chicken, Plymouth chicken, etc.; if both pigments are combined, olive or gray-green eggs will be produced, and the pigments are superimposed to produce more gradient colors.
By the way, let me tell you about the color of the egg yolk.
The attractive color of egg yolk is mainly derived from lutein, which generally comes from colored grains such as corn and green leaf feed such as alfalfa powder. The color of egg yolk is completely determined by the breed of layer and the composition of the feed and has little impact on the taste. Egg yolk is the most satisfying part of the taste. The rich lipid and protein make it have a thick emulsified texture and smooth taste. The higher the fat content, the more mellow the flavor.
Q3: How to judge the freshness of eggs?
A: Freshness is the most important factor in determining the quality and taste of eggs. The inside of an egg is mainly composed of three parts: thick egg white, thin egg white, and egg yolk. For eggs of similar size, the height and freshness of the yolk and egg white after cracking are proportional to the freshness. The fresher the egg, the "firmer and fuller" it is.
That's because the total amount of molecules in the egg yolk is more than that in the egg white, and the difference in osmotic pressure caused by this concentration difference creates an irreversible trend: the water in the egg white will always transfer to the egg yolk.
From the moment the egg is laid, a countdown starts. Every day, a small amount of water will transfer from the egg white to the yolk, which makes the yolk continue to expand. Flat, the vitelline membrane that wraps the egg yolk will eventually be broken, and the egg yolk overflows, which becomes what we often call "loose yolk eggs". At this stage, the eggs are already very stale.
Q4: How many eggs can a hen lay in a year?
A: Human domestication of chickens may be traced back to 7,500 years ago. It originated in the south of Eurasia, and then gradually spread to the whole world. Today, the dynamic number of domestic chickens on the earth is maintained at more than 20 billion, and each person can be assigned 3 chickens on average, far exceeding other poultry and livestock. We'll never know what motivated humans to domesticate jungle chickens in the first place, perhaps for delicious chicken, but more likely for high-yielding eggs.
Some birds lay a fixed number of eggs at once during the breeding season, while others, such as chickens, lay eggs multiple times until a certain number of eggs have accumulated in the nest. If the eggs are taken away by predators, they will make up for the missing eggs. This "obsessive-compulsive bird" produces a lot of eggs, just like an inexhaustible automatic egg-raising machine, which can drive greedy humans, I'm so happy.
After continuous domestication and breeding, countless high-quality laying hen breeds were finally born. Farmed laying hens can lay eggs every day, and only 2 kilograms of feed can be exchanged for nearly 1 kilogram of eggs. A hen can produce 20 kilograms of eggs a year. This kind of cheap food is amazing.
How much do you know about the structure and function of eggs？
Egg Whites: Also known as egg whites. Egg whites account for about 66% of the edible part of eggs. Egg whites contain more than half of the protein of a whole egg, as well as niacin, riboflavin, magnesium, potassium, sodium, etc., and almost no fat. Egg whites are a translucent jelly that turns white when stirred or cooked. The carbon dioxide in the egg makes the surface of the egg white cloudy, and as the storage time prolongs, the carbon dioxide volatilizes, the egg white becomes more transparent, the protein also denatures, and the egg white becomes thinner and thinner, which is why fresh eggs can be intact when opened. The ground is approximately upright in the egg tray and the reason why the eggs that have been opened for a long time are flat on the tray.
Yolk: About 34% of the edible part of an egg. It contains the fat of a whole egg and a fraction of the protein. Except for niacin and riboflavin, the vitamin content of egg yolk is higher than that of egg white. Almost all of the vitamins A, D, E, and K in eggs are in the yolk. In fertilized eggs, the yolk is where the embryo is formed.
Air chamber: The reason why eggs are easy to peel after cooking is because of the air chamber. There are two layers of shell membranes in the egg shell. After the eggs are laid, as the temperature drops, an air chamber will be formed between the two layers of membranes at the larger end of the egg. breathe.
Eggshell: 9%~12% of the total weight of the egg. The eggshell is the first line of defense against bacteria contaminating the inside of the egg. The main factors affecting eggshell strength are the mineral and vitamin content in the chicken feed, especially calcium, phosphorus, manganese, and vitamin D.
Eggshell membrane: a fibrous film located between the eggshell and the egg white, accounting for about 1% of the total weight of the egg, with a thickness of about 67 microns, and the main component is protein. What is the function of the eggshell membrane? An eggshell membrane is a semi-permeable hydrophilic bioactive membrane, which has good air permeability and moisture retention and can selectively absorb the substances it needs. In traditional Chinese medicine, the eggshell membrane is also called "Phoenix Clothes". It not only has the functions of nourishing yin and clearing lungs, reducing inflammation, and promoting skin growth but also can be used in cosmetics to make skin more delicate and smooth.
Lace: After a fresh egg is opened, there will be a light-colored flocculent elastic "rope" at both ends of the yolk, which is the frenulum, through which the yolk can be relatively fixed in the center of the egg. The more prominent the lace, the fresher the lace. It does not affect egg white quality and is edible.