- Egg breaker &separator, Egg cleaning machine, egg cracking/knocking machine ›
- News about egg washing machines and egg breaker ›
- Egg System Combing, Overview of Egg Varieties
Eggs have high nutritional value, and simple cooking is the choice of many families; eggs can be made into a variety of delicious desserts, mouthwatering. This article will introduce the egg system.
Definition of eggs
Eggs, also known as chicken eggs and chicken hens, are eggs laid by hens. They have a hard shell on the outside and air chambers, white and yolks inside. They are rich in various nutrients and are one of the foods commonly eaten by humans–. If the egg is fertilized, the chick will hatch after about 21 days.
Egg structure diagram
Classification of eggs
According to eggshell color: brown shell egg, white shell egg, powder shell egg;
According to species and production methods: soil eggs, feed eggs;
According to the storage method: fresh eggs, refrigerated eggs;
According to the processing method: liquid whole egg, liquid egg yolk, liquid egg white, egg freeze-dried powder;
According to quality standards: ordinary eggs, green eggs, organic eggs;
Egg quality standards and grading
Egg quality standards and grading are generally determined from two aspects:-the appearance inspection, and the second is light identification. When grading, attention should be paid to the cleanliness, color, weight, and shape of eggshells, the visibility and strength and location of egg whites, egg yolks, and embryos, and the size of air chambers.
(1) Quality standards for domestic fresh eggs
The purchase of fresh eggs is generally not classified into grades, and there is no uniform standard, but some regions have formulated purchase standards. Class I eggs: Regardless of chicken, duck, and goose breeds, regardless of size (except for young duck eggs), they must be fresh, clean, intact, and undamaged; Class II eggs: fresh in quality, with complete eggshells, stained with dirt or rain Drenched eggs; third-grade eggs: eggs with severely soiled shells and more than 50% of the area and young duck eggs
(2) Grading standards for fresh eggs
Class 1 eggs: Fresh eggs that have just been produced, the shell is firm and complete, clean and dry, the color is natural and shiny, and has the inherent fishy smell of fresh eggs. The air chamber is very small during fluoroscopy, no more than 0.8cm in height, and does not move. The egg white is thick and transparent, the yolk is located in the center, and there is no embryonic development.
Second-class eggs: Fresh eggs that have been stored for a longer period of time. The shell is firm and complete, clean, and slightly stained. During fluoroscopy, the air chamber is slightly larger, the height does not exceed 1.0cm, and does not move. The white is slightly thin and transparent, and the yellow is slightly larger and obvious, allowing it to deviate from the center, and turning slightly faster, and the embryo has no development.
Grade 3 eggs: It has been stored for a long time, and the outer shell is relatively fragile and thin, allowing stains on the shell. The air cell exceeds 1.2cm during fluoroscopy, allowing movement. The yellow is large and flat, and is markedly red, allowing the embryo to develop.
Common variables describing egg characteristics
The air chamber height is an important parameter for the quantitative evaluation of egg freshness based on the quality of the egg. It can be obtained by a special ruler according to a certain calculation method. The height of the air chamber is affected by the egg quality and the relative humidity in storage. Theoretically, the air chamber height of Class A eggs should be less than 6mm during the shelf life.
(2) Egg yolk index
The smaller the yolk index of an egg, the older the egg. The yolk index refers to the ratio of the height of the yolk to the diameter of the yolk or expressed as a percentage. The yolk index of fresh eggs is 0.38 -0.44, and the yolk index of qualified eggs is above 0.30.
(3) Huff unit
The Huff unit calculates an index based on the regression relationship between the height of the protein and the egg quality, reflecting the freshness of the egg. Many countries in the world use the Huff unit as an index for evaluating egg quality.
Changes during egg storage
The change of eggs is first of all quality changes, which are related to storage conditions such as temperature, humidity, eggshell thickness, and integrity. The higher the temperature, the faster the weight loss, and the higher the humidity, the slower the evaporation of water.
The change of the egg air chamber is directly related to the quality loss. When the egg leaves the mother, the temperature drop will cause the internal content of the egg to shrink, thereby reducing the pressure in the egg, and external air enters the egg through the stomata. At the same time, as the moisture and carbon dioxide diverge, the air chamber will increase. The size and change of the air chamber are closely related to the outside temperature, humidity, and the number of stomata on the eggshell, so it can be used to estimate the freshness of the egg.
During the storage of eggs, the thick protein gradually decreases, and the thin protein gradually increases. The content of the thick protein is closely related to the freshness. The index of the egg weight and the height of the egg is the Huff unit.
By analyzing the changes in the egg storage process, it can be concluded that the air cell height, the yolk index, and the Huff unit can all be used as objective indicators to describe the freshness of the egg.
How should eggs be stored?
Eggs in Chinese supermarkets are usually stored at room temperature. Many people buy them and put them in the refrigerator. Some careful people will clean the eggs before storing them. However, people in the United States, Japan, or Canada may find it strange because the eggs in supermarkets in these countries are kept in refrigerators. Eggs are kept at room temperature in supermarkets in most European countries. Actually
Except for a few countries such as the United States, Canada, Japan, and Australia, eggs in most countries are kept at room temperature.
The most important thing to preserve eggs is consistency. If you choose to wash and refrigerate at the beginning, then the whole process, until it is cooked and eaten in your mouth, needs to be refrigerated at any time. If you buy it from a refrigerated supermarket and store it at room temperature, the artificially plated protective oil on the surface of the egg will melt, the protective layer on the surface of the egg will be destroyed, and bacteria will take advantage of it.
In addition, keeping them in the refrigerator has another advantage, that is, the shelf life of eggs is extended from 21 days to 50 days.
Many countries choose to store eggs at room temperature instead of washing, because the cost of refrigeration after washing is too high, which is impractical for many countries. Another reason is that people in different countries have different understandings of whether eggs are beautiful or safe. People in North America and Japan seem to have an almost paranoid pursuit of the beauty of eggs. A little dirt on the surface of eggs is intolerable, so they have developed a model of cleaning and refrigerating. For people in most other parts of the world, the surface of the eggs is a bit dirty, which is not a problem at all, just wash them before eating.