Some people will find that the color of jiaozi bought home is not yellow but green, which is not normal. How is it that zongzi leaves are green after being cooked? The leaves cooked by zongzi are green. Can they be eaten? What is green zongzi leaf? What are the hazards of green zongzi leaves? Dong Jinshi, an expert in safety and environmental chemistry and secretary-general of the International Food Packaging Association, said that zongzi leaves on the market are divided into dry zongzi leaves and fresh-keeping zongzi leaves. Dry leaves are yellow-green, and fresh leaves are bright green. There are two main reasons why the leaves of fresh-keeping zongzi can remain bright green. One is to add preservatives (preservatives); In addition, industrial copper sulfate and industrial copper chloride are added to soak the leaves. The zongzi leaves bought by Ms. Li are probably "green" zongzi leaves, which are harmful to human body. It is best not to eat them. Fresh zongzi leaves are cooked at high temperature in the production process, and the color of zongzi leaves will be dark green, grayish black or light yellow, and there will never be turquoise zongzi leaves. In order to keep the leaves fresh and beautiful, some merchants use chemical dyeing method to add industrial copper sulfate and industrial copper chloride when soaking the leaves, so that the leaves that have lost their primary colors turn green, making their surfaces bright and their colors bright green. Excessive or long-term intake of copper by human body will cause a large amount of copper to accumulate in the liver, causing copper poisoning. This symptom is not easy to detect, once it appears, it may cause cancer and even endanger life. During the interview, the reporter found that some dumplings sold in supermarkets have a shelf life of 12 months, some are 9 months, and some are only 3 to 5 months. Investigators of the International Food Packaging Association believe that this is due to the differences in stuffing, packaging and storage methods of zongzi, as well as possible preservatives. Consumers are advised to choose zongzi with short shelf life and new production date. Comparison of how to choose green zongzi and normal zongzi (dish) Pay attention to "green zongzi leaves" when buying zongzi. When buying zongzi, don't covet bright green. Although the color of traditional air-dried zongzi leaves is old and dim, it is more natural and safe. At first glance, the color of the primary leaves is dark yellow, while the "turning green leaves" are even turquoise with bright surfaces; Smell it. jiaozi made of primary color dumplings will give off the fragrance of jiaozi when cooked. Cooked jiaozi will not only have a faint fragrance, but also have a faint smell of sulfur. Look at the boiled water. When jiaozi wrapped in primary color leaves is cooked, the boiled water will be light yellow, while the leaves of "jiaozi" will be relatively stable in color due to chemical treatment, and the boiled water will be light green after heating. If the green color is obvious, it means that the content of chemical raw materials is high.