According to a common saying in China's southern Guangdong province, aged dried tangerine peels are as precious as nuggets of gold. The preparation process for tangerine peels typically begins with sun-drying, followed by at least three years of storage. When the peels mature, they can be used to soothe coughs and combat phlegm.
During maturation, the essential oil in the citrus peel begins to dissipate and penetrate its entire surface. As it does so, it releases a mellow perfume, along with an antioxidant and anti-inflammatory substance known as flavonoids. The amount of flavonoids in the zests increases the longer they are stored, bringing up their medicinal value.
Dried tangerine peels have a lot of desirable qualities to practitioners of traditional Chinese medicine. In the Compendium Of Materia Medica, the work of Ming Dynasty herbalist Li Shizhen, the peels are said to “cure a hundred illnesses” and their ability to relieve body heat and dampness. The dried zests have a sharp and bitter taste and can help to nourish the spleen and lungs, and clear the throat of phlegm. Simply soaking them in hot water and then drinking the liquid is an effective remedy for coughs and phlegm.
Old is gold
Like fine wine, the cost of dried tangerine peels skyrockets with age. In general, a tael (38g) of 10-year-old peel goes for HK$50 (US$6.50). The price of the 35-year-old variety can go up to HK$300 per tael, while the 45-year-old ones can cost upwards of HK$500 per tael. To distinguish mature peels from younger ones, one-MICHELIN-starred restaurant Ming Court’s executive chef Li Yuet Faat explained that the aged ones have a darker hue and more complex and mellow aromas. They have a subtly sweet flavour, and are thinner and harder texture-wise. In contrast, zests that have been aged for a shorter time have a lighter colour and fragrance. They tend to be more bitter and have a softer texture.
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Cooking with tangerine peels
Apart from their medicinal benefits, dried tangerine peels often features in Cantonese cooking in a supporting role. There have been written accounts dating back to 1330, such as The Principle To The Right Diet, which recorded the use of tangerine peels in multiple recipes.
The fruity fragrance of the peels helps to remove the unpleasant tastes in game meat and the muddy flavours found in some fish and seafood, according to chef Li.
To use the rinds as a cooking ingredient, they have to be first softened by soaking them in water. The white inner side of the rinds needs to be scraped off so that its bitterness will not affect the overall flavour of the dish.
How to store tangerine peels
You will often find a piece of tangerine peel inside soups that have been boiled for hours. Li says this is because the peels play a "soothing function" and can turn down the “heat” of the soup. Li explained: “Soups boiled directly over fire tend to have a ‘hot’ medicinal property. Dried tangerine peels can nullify the body heat and soothe our throats as we enjoy the soup, while adding a delightful citrusy aroma.”
But Li cautions to use the peels sparingly: a small piece of dried tangerine peel should suffice for a pot of soup for four people. If a large amount is used, it could overshadow the taste of the meat and vegetables inside.
As for stews, dried tangerine peels are usually cooked with the other aromatics like garlic, shallot, Sichuan pepper and star anise. When the aroma becomes apparent, the sauce and the main ingredients are added to cook on low heat, said Li.
Whether used in medicine or cooking, dried tangerine peels require careful storage, ideally in airtight and metallic food containers, particularly to prevent them from getting damp. The peels should be taken out to dry under the sun once in a while to keep their smell fresh. Once a damp stench develops in the zests, no sunlight can get that out. The only thing you can do is throw them away, Li added.
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