Winter is the season for tangerines, and it's common to see people wash the peels after eating the fruit and use them to make tea, believing it is beneficial to their health. In fact, fresh tangerine peel and the aged tangerine peel (Chen Pi) used in traditional Chinese medicine are not the same; the fresh peel does not have the same medicinal properties and may even have adverse health effects when used to make tea.
As is well known, Chen Pi is made from the peel of mature tangerines that has been sun-dried or air-dried. The longer it is aged, the better its quality, and it is generally not used until it is at least a year old. After a year, the essential oil content in the peel decreases significantly, while the content of flavonoids increases. It is at this point that the medicinal value of Chen Pi is fully realized. Fresh tangerine peel, on the other hand, contains a high amount of essential oils and does not possess the same medicinal benefits as aged peel.
Another reason fresh tangerine peel is not suitable for making tea is that its surface can be contaminated with pesticides and preservatives, which are harmful to human health. To protect tangerine trees from pests and diseases, farmers spray pesticides multiple times from the flowering to the fruiting stages. Most of these pesticides do not break down easily and can remain on the surface of the fruit, making them difficult to remove. Furthermore, after harvesting, farmers often soak the tangerines in preservatives before they are sold to market. These preservatives inhibit surface bacteria and extend the fruit's shelf life. While they do not affect the pulp, some of these chemicals inevitably remain as residues on the peel. Using fresh tangerine peel with these residues to make tea can potentially have adverse effects on your health.