Problem description:
Delicious preserved eggs. Are the preserved eggs we eat a potential safety hazard? We should do it ourselves. Is there any way to make them lead-free?
Analysis:
Is lead-free preserved eggs really "lead-free"?
It's hot in summer, and a bowl of porridge and a preserved egg is disgusting. But preserved eggs have always been classified as unhealthy food.
In the past, some heavy metals, such as lead oxide or copper, were added to eggs to promote the coagulation of proteins. If eaten for a long time, lead or copper in it will cause chronic accumulation and affect health. Now, after improving the process, copper sulfate and zinc are used instead of lead oxide, hence the name "lead-free preserved egg". Many people think that preserved eggs are lead-free and should be bought for children.
In fact, "lead-free preserved eggs" do not contain lead at all, but the lead content is much lower than before. Although it has little effect on the health of adults, it is best for children to eat less or not, because children are very sensitive to lead, and the absorption rate in the intestine is as high as 50%.
Some people have detected Enterobacter citronellae and mold in preserved eggs, so vinegar, ginger and garlic should be added to eat preserved eggs. First, it can remove the alkaline smell, and second, it can sterilize. In addition, preserved eggs should not be stored for too long and the water evaporates too much. Preserved eggs will be as hard as rubber and not easy to digest.
Method for making lead-free preserved eggs
1. preparation of solution a: add 50 liters of water to two containers, add 2.5 kilograms of tea leaves to one container, and add 2.5 kilograms of fresh cypress leaves to another container, and boil each for 1 hour, then filter the liquid in the two containers into a container with 3 kilograms of salt. Add 25 liters of water to each of the two containers, and boil again 1 hour before use. After the salt in the third container is completely dissolved, take all the supernatant, boil it again, filter it into the boiling water in the two containers, and finally make up about 150 liters with cold boiling water, stir it evenly, and cool it to get solution A.
2. Preparation of solution B: Take 90 liters of solution A, 2 kilograms of salt and 300 grams of zinc sulfate, put them in a container, slowly add 6 kilograms of 96% sodium hydroxide in batches, cool them after dissolution, then add solution A until the solution is 100 liter, and stir evenly to obtain solution B. ..
3. Initial soaking: soak qualified fresh duck eggs (eggs, goose eggs and quail eggs) in solution B.. Pay attention to the fact that all eggs should be submerged 2 ~ 3 cm below the liquid level, and about 130 kg of eggs can be soaked in 100 liter of liquid B. Keep the temperature at 20 ~ 25℃ 13 days. At this point, the egg has solidified, but the flavor and color are not yet intact.
4. Re-soaking: 50 liters of used primary soaking solution for soaking eggs is mixed with 50 liters of solution A, which is re-soaking solution. Put the newly soaked eggs into the re-soaking solution, control the temperature at about 20℃, take them out, wash them and dry them 10 ~ 15 days.
5. Post-soaking treatment: the paraffin is melted, the temperature is controlled at about 90℃, the re-soaked eggs are put into paraffin liquid, taken out after 3-5 seconds, and the finished product is obtained after cooling. Paraffin 1.2 ~ 1.5 kg is needed for every 50 kg of eggs.
Preserved eggs made by this method not only contain no lead, but also contain high zinc, which is beneficial to human body. The shelf life is long, usually 6 months.