2. Preserved eggs may have evolved from salted duck eggs recorded in the Book of Qi Yaomin in the Northern Wei Dynasty. A clearly recorded preserved egg was written in the 17th year of Emperor Xiaozong of the Ming Dynasty (1504), in the house miscellaneous department of Zhuyushan.
3. There are black spots on the surface of eggshell, indicating that the content of lead and copper in preserved eggs is relatively high. After the eggshell is peeled off, some protein may appear dark green or have black spots, which is the result of the reaction between sulfur produced by protein decomposition and metal ions (such as copper ions). Traditional preserved eggs are preserved with fresh duck eggs, edible alkali, edible salt and quicklime for more than two months.
4. But in order to shorten the production cycle and reduce the cost, some unscrupulous manufacturers use industrial copper sulfate for pickling. Such preserved eggs will increase the burden on the liver and kidney, and long-term consumption in large quantities will easily lead to heavy metal poisoning.
1. The main raw materials for making preserved eggs are quicklime, soda ash, salt, black tea and plant ash.
2. Preserved eggs may have evolved from salted duck eggs recorded in the Book of Qi Yaomin in the Northern Wei Dynasty. A clearly recorded preserved egg was written in the 17th year of Emperor Xiaozong of the Ming Dynasty (1504), in the house miscellaneous department of Zhuyushan.
3. There are black spots on the surface of eggshell, indicating that the content of lead and copper in preserved eggs is relatively high. After the eggshell is peeled off, some protein may appear dark green or have black spots, which is the result of the reaction between sulfur produced by protein decomposition and metal ions (such as copper ions). Traditional preserved eggs are preserved with fresh duck eggs, edible alkali, edible salt and quicklime for more than two months.
4. But in order to shorten the production cycle and reduce the cost, some unscrupulous manufacturers use industrial copper sulfate for pickling. Such preserved eggs will increase the burden on the liver and kidney, and long-term consumption in large quantities will easily lead to heavy metal poisoning.
1. The main raw materials for making preserved eggs are quicklime, soda ash, salt, black tea and plant ash.
2. Preserved eggs may have evolved from salted duck eggs recorded in the Book of Qi Yaomin in the Northern Wei Dynasty. A clearly recorded preserved egg was written in the 17th year of Emperor Xiaozong of the Ming Dynasty (1504), in the house miscellaneous department of Zhuyushan.
3. There are black spots on the surface of eggshell, indicating that the content of lead and copper in preserved eggs is relatively high. After the eggshell is peeled off, some protein may appear dark green or have black spots, which is the result of the reaction between sulfur produced by protein decomposition and metal ions (such as copper ions). Traditional preserved eggs are preserved with fresh duck eggs, edible alkali, edible salt and quicklime for more than two months.
4. But in order to shorten the production cycle and reduce the cost, some unscrupulous manufacturers use industrial copper sulfate for pickling. Such preserved eggs will increase the burden on the liver and kidney, and long-term consumption in large quantities will easily lead to heavy metal poisoning.
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