The preserved egg is a unique egg processed food in China. It is a typical egg processed product with a special flavor and can promote appetite. According to "Medical Forest Ministries," it says that it can "swollen the lungs and heat, sober up, go to large intestine fire, and cure diarrhea. Can be scattered, can converge", the workshop is commonly used to treat sore throat, throat treatment, hoarseness, constipation.
People often hear that preserved eggs cannot be eaten. In fact, they are mainly concerned with the fact that preserved eggs contain lead from heavy metals. However, they need not be too frightened because they can be avoided by paying only a little attention at the time of purchase. Remember to check the surface of the preserved eggshell for black spots of different sizes. If so, avoid eating.
The key to making preserved eggs is whether or not the protein inside is completely gelled. Therefore, during the production process, it must be immersed in a strong alkali solution to achieve protein denaturation and produce special flavor and color. However, in order to avoid gelation and reliquefying it, resulting in deterioration of the finished product, lead oxide, copper sulfate, and methionine are usually added to the alkali liquor to prevent reliquefaction. The residue of lead that people are worried about is the residue of this chemical in the eggshell.
The nutritional value of preserved eggs is generally: iron-rich, methionine (required amino acids), vitamin E (the above is compared with eggs). The disadvantages are that the proteins degraded by lye do not easily absorb, and the LAL (lysinoalanine) in denatured proteins has unproven kidney lesions in animal experiments.
If it is considered to increase the changes in the daily diet and tasting of special flavors, preserved eggs are a food that can be considered, but if it is based on nutritional value, it seems that there are other better choices. As for the problem of lead residue, it can only be judged by consumers' appearance at the moment, but I already know that there are many food industry experts who rely on temperature control to develop ways to maintain the quality of preserved eggs without having to add lead oxide. I believe Soon, consumers can eat preserved eggs that do not need to worry about heavy metal residues.