Raw materials: The main raw material for processing preserved eggs is duck eggs. In addition, soda ash, lime, salt, tea, yellow red powder, plant ash, pine and cypress branches, etc. are also used. 1. Selection of duck eggs: Fresh eggs of good quality must be used for processing preserved eggs in order to meet the quality standards of high-quality products. 2. Materials and their functions The materials used in processing preserved eggs must also meet quality requirements in order to produce high-quality preserved eggs that meet standards. (1) Quicklime. It can denature and solidify the protein of duck eggs and make it jelly-like. In addition, in order to ensure the concentration of alkali solution, the quicklime used must not be affected by moisture or be left in the open air for a long time. (2) Soda ash. (3) Huangdan powder. That is lead oxide, also known as Tantra. Its main functions are twofold: first, it gives the egg whites a unique bluish-black color; second, it keeps the egg whites at a certain hardness after coagulation, making them easier to peel and keeping the beginning intact after peeling. (4) Table salt. It can weaken the spicy taste of preserved eggs, improve the flavor of preserved eggs, inhibit the activity and reproduction of harmful microorganisms, and promote the formation of soup center in egg yolk. However, the amount of salt should not be too much. If it is too much, the coagulation power of the egg white will be poor and the egg yolk will become hard. (5) Tea. Tea contains tannins, which help to coagulate egg whites, improve the color of preserved eggs, and soften the spicy taste. (6) Plant ash. Contains Na2CO, which helps the coagulation of protein. (7) Pine and cypress branches. Contains special-smelling resins and aromatic substances that help improve the flavor of preserved eggs. 2. Processing principle 1. Characteristics of prepared preserved eggs: the eggshell is easy to peel off, the egg white is solidified, and is light green brown or brown translucent jelly-like. There are pine needle-like white crystals or patterns in the brown egg white, and the egg yolk is It is semi-solidified. The yolk can be clearly divided into different colors such as dark green, earthy yellow, gray green, orange, etc. There is a soup center in the egg yolk. The finished product has a unique flavor, rich aroma, little spicy taste, and a refreshing feeling after eating. 2. Processing principle Fresh duck eggs can be made into preserved eggs with the above characteristics because the content of duck eggs is formed under the combined action of various materials during the transformation process. The main role is sodium hydroxide, which gradually penetrates into the protein during processing and promotes coagulation of the protein. 3. Processing methods Although there are many processing methods for preserved eggs, the main processes are similar with some differences as follows: 1. Ingredients The ingredient standards for preserved eggs produced in my country vary from place to place. The ingredient standards for Beijing, Tianjin, Hubei and other regions are listed as follows. Table 1 Standard reference table of preserved egg ingredients Region and season Amount (kg) Ingredients Beijing Tianjin Hubei Spring Autumn Summer Spring Early Autumn Late Summer First, fourth quarter, second and third quarter Fresh duck eggs 400 400 400 500 500 500 Quicklime 14-15 15-16 14 15 16-17.5 17.5-18 Soda ash 3.5 3.75 3.75 4-4.25 3.25-3.5 3.75 Huangdan powder 0.15 0.15 0.15 0.15 0.1-0.15 0.1-0.15 Salt 2 2 1.5 1.5 1.5 1.5 Tea 1 .5 1.5 1.5 1.5 1.57 2 Charcoal Ash 1 1 25 -3 3.5 Pine and cypress branches 0.15 0.15 A little yellow mud 0.5 0.5 Clear or cooked water 50 50 50 50 50 50 It can be seen from the ingredient standard reference table that the ingredient standards have also changed according to climate and seasonal changes in various places. Among them The amounts of the main materials, namely quicklime and soda ash, vary. Similarly, the quality of duck eggs in summer is not as high as that in spring and autumn. Soon after the eggs are placed in the tank, the yolk will float and deteriorate. For this reason, the dosage standards of quicklime and soda ash should be appropriately increased to accelerate the maturity of preserved eggs and shorten the maturity period. The quicklime in the ingredients should be white lump ash with high purity and low impurity content: yellow lime powder (do not use excessive amount, otherwise it will increase the lead content in the mouth). It is better to choose light yellow, whose quality is relatively pure and has the best effect. better. When making ingredients, they must be ground and sieved, the finer the better, to avoid "pig eyes" (that is, the granular yellow red powder corrodes the protein and makes the protein appear black spots), which affects the quality of the finished product. 2. Boil the ingredients: First, wash the pot clean, and then pour the accurately measured soda ash (or purple alkali), salt, tea leaves, pine and cypress branches, and water into the pot according to the ingredient standards and heat it to boil. 3. For punching, prepare an empty cylinder (thick cylinder) or iron bucket. First weigh the quicklime and put it into the cylinder (or bucket), and then put the yellow dandelion powder and plant ash on top of the quicklime. Then pour the above-mentioned boiled water (or juice) into the vat while it is still boiling. At this time, the quicklime will melt on its own when it encounters the juice. At the same time, it will release heat and emit high temperature. After the evaporation force in the vat gradually weakens, use a shovel to stir and stir continuously. Evenly. 4. Loading the vat and filling the soup. Put the selected fresh duck eggs into a clean vat by grading or dividing them into different sizes. Before placing it in the tank, a layer of clean wheat straw should be spread at the bottom of the tank to prevent the duck eggs in the lowest layer from directly colliding with the hard bottom of the tank and being damaged by the pressure of the many layers of duck eggs above. When placing eggs into the jar, handle them gently and lay them flat one layer at a time. Install it about 6-10 cm away from the mouth of the tank, add a colorful bamboo grate cover, and press it with a wooden stick to prevent the duck eggs from floating after filling the soup. After installing the tank, stir the cooled liquid (or soup) to make the concentration uniform, and slowly pour the required amount into the tank from one side of the tank until all the duck eggs are submerged in the soup.