1. How to make preserved eggs

Ingredients for making preserved eggs *** Picture: 1. Boil the preserved eggs in water, soak in cold water and cool.

This will allow the yolk of the preserved egg to solidify and cut easily without sticking to the knife. 2. Peel the cooled preserved egg and find a beautiful snowflake pattern. It’s so amazing that I still find it fun. 3. Peel the preserved egg. Cut the preserved eggs into small dices 4. Chop the chives into small pieces, smash the almonds with a knife, cut the red pepper into small dices, and chop the coriander into small pieces. 5. Cut a few lines into the lactone tofu and put it on a plate. 6. Sprinkle the tofu with fine salt. All the ingredients are poured with sesame oil, red oil, swastika soy sauce, and sprinkled with chopped almonds. Dietary taboos: Preserved eggs should not be eaten with turtles, plums, and brown sugar. Diet Tips 1. The simplest way to eat preserved eggs is to mix vinegar, minced ginger, sesame oil, and light soy sauce into a good sauce. The preserved eggs can be steamed or boiled, then peeled and cut into small pieces (steaming is mainly to allow them to set their shape) Solid, not egg yolk and sticky) Just pour the mixed juice on top. If you add the method of mixing shallots with tofu and add diced preserved eggs, it will become delicious preserved egg tofu. If you mix the tofu with steamed Sliced ??preserved eggs fried with dried chili segments, green onions, Sichuan peppercorns, and pine nuts are the "Kung Pao Preserved Eggs" I made in Beijing TV's "Happy Life" and it tastes pretty good, so try eating it another way.

2. Thousand year egg in English means thousand-year egg, also called preserved egg. Preserved eggs are 100% a delicacy of the Chinese people. Many countries still can’t understand why the Chinese like it, just like we can’t understand why they like to eat stinky cheese.

3. There is actually something special about eating preserved eggs. It is not like eating boiled eggs. The more elaborate ones are paired with ginger vinegar and a little light soy sauce. The taste is different, with a little bit of crab. The taste of the egg yolk meets the perfectly cooked egg without being runny. Cut a whole preserved egg into four small petals, each petal contains egg white and egg yolk, whether it is a salted egg, a braised egg, or a preserved egg, In short, the egg yolk is the most delicious. The salted egg yolk is rustic and the more you eat it, the more delicious it becomes. The braised egg is like meat with braised flavor. I can’t express the preserved egg in words, but when I write it, I still feel that it tastes good in my mouth. It feels so delicious that you can’t stop eating. The egg white is fresh and elastic. Of course, sometimes when the cooking is not good, the egg yolk will appear runny. At that time, the yolk of the cut preserved egg will flow out and sit at the bottom of the plate. The watery ones always lack the mature fragrance, but they don’t have a different taste. In addition, because a lot of protein in the yolk of preserved eggs is decomposed into amino acids, the yolks of preserved eggs taste much fresher than the yolks of ordinary eggs. Although preserved eggs are rich in nutrients and delicious, they are too alkaline, so It is not advisable to eat too much.

4. I have a feeling about eating preserved eggs, that is, when eating preserved eggs, you must cut them into small pieces and eat them piece by piece slowly. In fact, I am the kind of person who devours his meals. , but every time I eat it, I feel that eating it that way is the most memorable. Don't mix it with other vegetables, otherwise it won't taste fragrant, and don't eat it with drinks or fruits containing vitamin C, otherwise the preserved eggs will become bitter in your mouth.

2. What are the tips for handling preserved eggs?

When peeling preserved eggs, sometimes the eggshell is peeled off along with the meat.

If you peel off the big end of the egg first, knock a small hole in the small end, and then blow air hard, the egg body will be easily peeled off with the momentum of the air flow. Falling out of the shell not only saves time and effort, but also keeps the preserved eggs intact and beautiful. Although preserved eggs taste good and have a smooth texture, they tend to stick to the knife when cut, resulting in the loss of a large amount of preserved egg yolk.

At this time, just take a piece of sewing thread about 30 cm long, hold one end of the thread in your hand, bite the other end with your teeth, and use a saw to cut the preserved egg. This is convenient and saves trouble. In addition, you can also apply a small amount of cooking oil on both sides of the knife to prevent it from sticking to the knife when cutting.

You can also steam the preserved eggs in a steamer for two minutes before cutting them, so that they won’t stick to the knife when you cut them again.

3. Chemical knowledge in the preparation of preserved eggs

The process of processing fresh eggs into preserved eggs is essentially a complex chemical reaction process. Although there are many recipes and different techniques for processing preserved eggs, the main raw materials are Generally include: quicklime (CaO), soda ash (Na2CO3), plant ash (main component K2CO3), salt, tea, etc. Based on the actual situation of the students, only 2 preserved eggs are used to describe the processing and chemical principles in the laboratory:

l. Ash recipe

Preserved eggs on the table taste very delicious but are covered with an ugly coat. Don’t underestimate them. The key ingredients for making preserved eggs are: 50g quicklime, 3g soda ash, plant ash. 1g, 2g salt, 20g water, trace amount of tea

2. Ash preparation

According to the requirements of the ash recipe, put the required ash into a container (i.e. a large beaker) and prepare quicklime with water. When it reacts with water, it generates hydrated lime. The hydrated lime undergoes a metathesis reaction with soda ash and potassium carbonate, the main component of charcoal, to form sodium hydroxide and potassium hydroxide. The reaction chemical equation is expressed as follows:

CaO H2O=Ca(OH)2

Ca(OH)2 Na2CO3=CaCO3↓ 2NaOH

Ca(OH)2 K2CO3= CaCO3↓ 2KOH

Prepare the ingredients to fully react 24 It can only be used after 1 hour

3. Processing of preserved eggs

Prepare the fresh eggs and roll the ash a few times to evenly coat the surface of the eggshell with ash powder. Take it out and roll it a few times with rice bran or sawdust. Apply a layer of rice bran or sawdust to the ash material and gently squeeze it with your hands to tighten it. Place it in the container prepared in advance. Treat the second fresh egg in the same way. Store it in a sealed container at an ambient temperature of 18~24℃ for 10 days.

During the 10-day change process, the inside of the egg is also like a deep water. Strong alkali (NaOH, KOH) penetrates into the egg white and yolk through the egg shell and interacts with the protein, causing the protein to decompose, solidify and release a small amount of hydrogen sulfide (H2S) gas. The infiltrated alkali will also decompose the protein and further produce and react with amino acids to form salt crystals, deposit gel peptides, and white pine flowers will appear on the egg white (which is also the reason why preserved eggs are named). Hydrogen sulfide gas reacts with the minerals of egg white and yolk to form Various sulfides change the color of egg whites and egg yolks. The egg whites take on a special dark brown color while the egg yolks turn dark green. Salt causes the preserved eggs to shrink and separate from the shell, increasing the taste. Tea tannins and aromatic oils can color the coagulated protein and increase the flavor of the preserved eggs.

Preserved eggs will go bad after half a month to several months because they contain salt which has a preservative effect; alkaline substances kill bacteria that can cause protein spoilage in fresh eggs

10 days When you sit at the dining table and taste the preserved eggs, your heart will be overflowing with joy, and you will also be thinking about making more. Next time when you are preparing to make a large batch, don’t forget to change the ash ingredient formula according to the proportion

4 .Tips of life, did you know?

The most painful thing for people who like to eat preserved eggs is that they don’t know how to choose high-quality preserved eggs. They often buy the preserved eggs with joy when they go home and open them. Go be a "badass". Find someone to reason with? It’s really not worth the time, effort, and breath. Don't tell me! It’s really annoying!

Here is a good way to choose high-quality preserved eggs. That is to use one look, two shakes and three weighs

One weigh: Put the preserved eggs in the palm of your hand and weigh them gently. Good quality preserved eggs will tremble a lot, while those without trembling will be of poor quality. .

The second shake: take the preserved eggs with your hands, put them next to your ears and shake them. Good quality preserved eggs have no sound, while poor quality ones have a sound; and the louder the sound, the worse the quality, and even bad or smelly eggs. Egg.

The third step is to look at the shell: peel off the mud attached to the egg and look at the shell. The eggshell that is intact, gray and white in color, and has no black spots is the top grade; if it is a cracked egg, during the processing Too much alkali may penetrate into the egg whites, which may affect the flavor of the egg whites. At the same time, bacteria may invade from the cracks and cause the preserved eggs to deteriorate.

5. Chemical knowledge about the production of preserved eggs

Preserved eggs are a unique processed egg product in China and are also an alkaline food.

The materials required for pickling preserved eggs include salt, tea and alkaline substances (such as quicklime, plant ash, sodium carbonate, sodium hydroxide, etc.).

The reason why preserved eggs have a special flavor is that after the action of a strong alkali, the original sulfur-containing amino acids are decomposed to produce hydrogen sulfide and ammonia. Coupled with the smell of the ingredients in the dipping solution, they produce It has a unique taste. The color of preserved eggs is due to the fact that under the action of strong alkali, the protein part will turn reddish brown or dark brown, and the yolk will turn dark green or orange red.

Where did the pine flowers on the preserved eggs come from?

It is actually produced through a chemical reaction: the main chemical component of protein is a protein. When eggs are left for a long time, part of the protein in the egg whites will break down into amino acids. Its chemical structure has a basic amino group -NH2 and an acidic carboxyl group -COOH, so it can interact with both acidic and alkaline substances.

So when people are making preserved egg designs, they deliberately add some alkaline substances to the mud. Such as lime, potassium carbonate, sodium carbonate, etc. They pass through the pores on the eggshell and combine with amino acids to form amino acid salts. These amino acid salts are insoluble in protein, so they crystallize out in certain geometric shapes, forming beautiful pine flowers.

Why is the yolk of preserved eggs bluish black?

In fact, this is also caused by a chemical reaction: the main chemical component of preserved eggs is another protein, which contains sulfur. Over time, the egg yolk will decompose into amino acids and release hydrogen sulfide, a gas that we usually call rotten egg smell. Egg yolk itself contains many minerals, such as iron, copper, zinc, manganese, etc. Hydrogen sulfide can react with these minerals to form sulfide.

Therefore, the bluish-black color of egg yolk is due to the production of these sulfides. Most of these sulfides are extremely insoluble in water, so they are not absorbed by the body. In addition, because a lot of protein in the yolk of preserved eggs is decomposed into amino acids, the yolks of preserved eggs taste much fresher than those of ordinary eggs. Although preserved eggs are rich in nutrients and delicious, they are too alkaline and should not be eaten in large quantities. Suggestion: When eating preserved eggs, add a little vinegar. Vinegar can sterilize and neutralize part of the alkalinity of preserved eggs, making them taste more delicious.

6. Use chemical knowledge to explain: the production of preserved eggs

Use 50g of quicklime, 3g of soda ash, 1g of plant ash, 2g of salt, 20g of water, trace amounts of tea, etc. Wrap it in the skin of fresh eggs, seal it in a sealed container, and place it at an ambient temperature of 18 to 24 degrees Celsius. It can be eaten after 10 days.

There are two main chemical reactions:

1. Chemical reaction of ash. Quicklime first reacts with water to produce hydrated lime, and then the hydrated lime reacts with soda ash and potassium carbonate, the main component of charcoal, to produce sodium hydroxide and potassium hydroxide. In order to allow the substances in the hair ingredients to fully react, it can only be used 24 hours after preparation.

CaO H2O=Ca(OH)2

Ca(OH)2 Na2CO3=CaCO3↓ 2NaOH

Ca(OH)2 K2CO3=CaCO3↓ 2KOH

2. Chemical reaction between eggs and ash. The strong alkali (NaOH, KOH) in the ash penetrates into the egg white and egg yolk through the egg shell, and interacts with the protein in it, causing the protein to decompose, solidify and release a small amount of hydrogen sulfide (H2S) gas. At the same time, the infiltrated alkali will further neutralize the amino acids decomposed from the protein. The resulting salt crystals are deposited in the preserved egg whites of the gel peptide, and white "pine flowers" appear (this is also the name of preserved eggs). reasons). The hydrogen sulfide gas reacts with the minerals in the egg white and yolk to generate various sulfides, so the color of the egg white and egg yolk changes. The egg white takes on a special dark brown color and the egg yolk takes on a dark green color.

The protein decomposes and solidifies and becomes transparent.

7. Tips on how to choose preserved eggs

Selection of preserved eggs 1. Weigh the preserved eggs gently in the palm of your hand. Good quality preserved eggs The quality of preserved eggs with large tremors and no tremors is poor.

2. Shake the preserved eggs with your hands, put them next to your ears and shake them. Good quality preserved eggs will have no sound, while poor quality ones will have a sound. The louder the sound, the worse the quality, or even bad or rotten eggs. 3. Look at the shell, that is, peel off the mud attached to the preserved egg. If you look at the shell, the eggshell is intact, gray-white, and has no black spots. If it is a cracked egg, too much may penetrate into it during the processing. Alkali will affect the flavor of the protein, and bacteria may also invade from the cracks, causing the preserved eggs to deteriorate.

4. Taste the preserved eggs. If the pickled eggs are qualified, the egg white will be obviously elastic, dark brown with pine branches pattern, the periphery of the egg yolk will be dark green or blue-black, and the center will be orange-red. Such pine flower After the egg is cut, the color of the cross-section of the egg is diverse, and it has the characteristics of good color, aroma, taste and shape.