100-year egg

food

abstract

Also known as preserved eggs, preserved eggs and so on. , a traditional flavor egg product in China, is not only deeply loved by domestic consumers, but also famous in the international market.

kind

Lead-free preserved eggs: lead oxide (yellow lead powder) is added to the traditional preserved egg processing formula in China. Because lead is a toxic heavy metal element, some countries have made regulations prohibiting the sale, which has affected the sale of preserved eggs exported to China. Therefore, the relevant scientific research departments have studied the substitute substances of lead oxide, among which EDTA and FWD have better effects. When EDTA (ethylenediamine tetraacetic acid) is used, the formula and processing technology of other auxiliary materials remain unchanged, as long as lead oxide is removed and EDTA is used instead. Generally processing 1000 duck eggs, the dosage is 0. 12 ~ 0. 13 kg. FWD is a substance synthesized by trace elements magnesium and manganese. Its usage is to dissolve 0.5 kg FWD in 75 kg cold boiled water to make 1500 duck eggs. The formula and processing method of other auxiliary materials are the same as when lead oxide is used.

Product characteristics

Finished preserved eggs, eggshells are easy to peel and do not adhere, the protein is translucent brown solidified body, the surface of the protein has pine-like patterns, the yolk is dark green solidified, and some have sugar hearts. The cut egg pieces are mottled and rotten. The food is cool and refreshing, fragrant but not greasy, and delicious.

quality test

The quality inspection and grading of preserved eggs is the last important process for manufacturers and should be carried out in accordance with relevant state regulations. Consumers should also make choices when buying goods. The commonly used methods for quality inspection of preserved eggs are: first observation, second weighing, third shaking and fourth photographing.

One view: Look at whether the packaging material is moldy, whether the eggshell is complete and whether the shell color is normal (the green cylinder color is better).

Second, put the egg in your hand, gently throw it up and throw it several times in a row. If you feel elastic and trembling, the heavier egg is a good egg, otherwise it is a poor egg.

Three shakes: hold both ends of the egg with your thumb and middle finger, shake it up and down in your ear, and hear the sound of water or impact. If you can't hear the sound, it's a good egg.

Photo 4: If most eggs are black or dark brown and a few are yellow or light red, they are high-quality eggs. If most of them are yellow-brown transparent body, they are immature preserved eggs.

manufacture

How did the pine flowers on the pine eggs come from? Is actually produced by a chemical reaction:

The main chemical component of protein is a kind of protein. When eggs are kept for a long time, some protein in protein will break down into amino acids. Do you know amino acids? Its chemical structure has a basic amino group -NH2 and an acidic carboxyl group -COOH, so it can react with acidic and alkaline substances. Therefore, people deliberately added some alkaline substances, such as lime, potassium carbonate and sodium carbonate, in the design of making preserved eggs. They will pass through the holes in the eggshell and combine with amino acids to form amino acid salts. These amino acid salts are insoluble in protein, so they crystallize in a certain geometric shape to form beautiful pine flowers.

Why is the yolk of preserved eggs bluish black? In fact, this is also caused by chemical reactions:

The main chemical composition of preserved eggs is another kind of protein, which contains sulfur. After a long time, the egg yolk will also decompose into amino acids, and release what we usually call rotten egg-flavored gas-hydrogen sulfide. Egg yolk itself contains many minerals, such as iron, copper, zinc and manganese. Hydrogen sulfide can react with these minerals to form sulfide. Therefore, the blue-black yolk is the source of these sulfides. Most of these sulfides are extremely insoluble in water, so they are not absorbed by the human body.

In addition, because a large amount of protein in preserved egg yolk is decomposed into amino acids, the yolk of preserved egg tastes much fresher than ordinary eggs. Preserved eggs are nutritious and delicious, but they are too alkaline to eat.

Suggestion: Add some old vinegar when eating preserved eggs, which can sterilize, neutralize some alkalinity of preserved eggs and taste more delicious.

side effect

Many people know that preserved eggs contain lead, so people buy lead-free preserved eggs and think they can eat them safely. In fact, lead-free preserved eggs also contain lead, which is ok for adults, but children should eat less.

When processing preserved eggs, soda ash, lime, salt and yellow lead powder should be mixed in a certain proportion, and mud and bran should be wrapped outside the duck eggs. Two weeks later, the delicious preserved eggs are ready. Plumbum preparatium powder is lead oxide, which can make eggs produce beautiful patterns, but with Plumbum preparatium powder, preserved eggs will be polluted by lead. According to the national regulations, the lead content of preserved eggs per1000g should not exceed 3mg, and preserved eggs that meet this standard are also called lead-free preserved eggs. Therefore, "lead-free preserved eggs" are not lead-free, but lead content is lower than the national standard.

Chinese medicine believes that children's bodies are "young yin and young yang" and their metabolism is extremely vigorous. Trace lead in "lead-free" eggs will remain in tissues such as liver, lung, kidney, brain and red blood cells after being absorbed by children, and will also cause calcium loss in bones and teeth. Regular consumption of "lead-free preserved eggs" will cause bone and tooth dysplasia, loss of appetite, gastroenteritis and so on. In children, it will also affect intellectual development.

Lead-free preserved eggs are delicious and nutritious, but children are in a stage of vigorous physical development and have obvious reactions to the harm of lead, so it is better to eat less.

Summer is hot, and most people like to entertain themselves with preserved eggs when drinking beer, or treat the whole family with cold preserved eggs. It may never occur to them that preserved eggs may also cause food poisoning.

According to the inspection and analysis of relevant food experts, there are only 400-500 bacteria on clean eggshells, while there are as many as10.40-0.40 billion bacteria on dirty eggshells. If these bacteria enter the egg in large quantities through the pores of the eggshell, eating such preserved eggs will be poisoned. When buying preserved eggs, it should be noted that the protein of preserved eggs is dark brown transparent body after peeling, which has certain toughness; Contaminated preserved eggs are light green, with poor toughness and easy loosening. Such preserved eggs must not be eaten.

Salmonella is the main bacterium that pollutes preserved eggs. After it enters the human body with preserved eggs, it causes inflammation on the intestinal trace membrane. After bacterial division, it will produce highly toxic endotoxin, which will cause poisoning symptoms.

Experiments have confirmed that Salmonella will die immediately at a high temperature of 100 degrees Celsius, at 70 degrees Celsius for 5 minutes and at 60 degrees Celsius 15-30 minutes. Therefore, when eating suspicious preserved eggs, you can steam the shelled eggs at high temperature for about 5 minutes, and then you can eat them safely after cooling. The suitable temperature for the growth of Salmonella is 20℃-37℃, and the temperature in summer and autumn is just within this range, so people should pay special attention to prevent preserved egg poisoning.