soft-shelled turtle
Water Fish
Dear friends:
Hello, everyone! As we all know, Hunan Province gets its name from Dongting Lake because it lies to the south of the lake, and this also determines that Hunan's specialty products must be related to the lake and named after water. Hunan is surrounded by mountains on three sides, with terrain high in the southwest and low in the northeast. The four rivers of Xiang, Zi, Yuan, and Li originate here, flow convergently into Dongting Lake, and then empty into the Yangtze River. Crisscrossing rivers and lakes form a dense water network; the nourishment and bounty of the mountains and waters have created rich and beautiful natural resources. Since ancient times, it has enjoyed the reputation that "when Huguang is ripe, the whole realm has enough." In addition, with four distinct seasons, a warm and humid climate, abundant products, and a prosperous people, it has long been known as "a land of fish and rice."
This superior natural environment and abundant resources provide favorable natural conditions for the growth of various organisms. Hunan is also famous for its rich specialty products. Water fish is one of Hunan's specialties, and the vast watery region of Dongting Lake is its home.
Water fish is commonly known as soft-shelled turtle, tuan yu, yuan yu, jiao yu, wangba, shenshou, and so on. It is a reptile with a carapace on its back, a round body with a fleshy rim, a long neck and short tail, four limbs with five claws, horny scutes on the skin, and soft skin covering the body. Because "the turtle moves in a shrunken way, it is called bie"; because its whole body is armored like a warrior, it is called "jia yu" (armored fish); or because its body is flat, oval, and round like a ball, it is called "tuan yu"; because it has four legs on its belly and crawls everywhere, it is called "jiao yu"; and because it lives in water, it is also called "water fish."
The water fish is a mainly carnivorous omnivorous amphibian. It feeds on small fish, small shrimp, earthworms, snails, mussels, and animal viscera, while a small amount of tender stems of aquatic plants and vegetables, melons, and fruits serve as supplementary food. The Dongting Lake water system is well developed with a dense river network, making it the best place for its survival; the interlocking water and land and the abundance of fish and shrimp provide ample food sources. The water fish has the characteristic of hibernation. It is a poikilothermic animal, very sensitive to changes in external temperature, and its most suitable growth temperature is 28°C to 32°C. Hunan's suitable climate is very favorable for their survival. When the water temperature drops to 20°C, the water fish enters hibernation, generally spending it in sandy mud about 2 to 3 meters deep at the bottom of the water. During hibernation, it does not eat or move and appears in a state of suspended animation, relying on gill-like tissues in the pharynx to absorb dissolved oxygen from the water in order to maintain minimal life activities during hibernation.
The meat of the water fish is delicious and rich in nutrients. Since ancient times, it has been a delicacy with excellent flavor and also a precious raw material for nutritious and health-care foods and a traditionally popular export product. It not only has high nutritional value but also great medicinal value. According to the Book of Songs, as early as the Zhou Dynasty, emperors regarded the water fish as a precious food to entertain distinguished guests and meritorious ministers: "Drink and present to all friends, roast the turtle and slice the carp."
The meat of the water fish is fattest and most tender in spring and autumn. In spring, it is called "cauliflower water fish"; in autumn, after the breeding period, the body is fat and the flavor is fresh, so it is called "osmanthus water fish"; in winter, the turtle hibernates and is extremely precious. In the Jiangnan region, there is the praise that "winter turtle and summer eel" are best. Since ancient times, Dongting water fish has been the finest under heaven, and Hunan chefs have their own unique skills in cooking it. "Steamed water fish skirt edge," "original juice Wuling soft-shelled turtle," and "braised soft-shelled turtle" are tender, richly fragrant, and delicious, making them excellent dishes for entertaining distinguished guests. But whether it is "steamed (whole) water fish (soft-shelled turtle)" or "red-braised water fish skirt and claws," the main ingredient must be wild water fish from rivers around Wuling Town in Changde; dishes made with water fish produced there, whether braised or steamed, have a particularly mellow fragrance and an especially fresh and long-lasting taste. Therefore, wild water fish from Changde is considered the best. Over the long years, people in the Dongting Lake area have also developed the convention of eating water fish with "turtle intestines and turtle gallbladder," meaning that when cooking water fish, one must not throw away the bitter gallbladder but should put it into the pot together with the water fish. In addition, turtle intestines are often put in to cook together as well. This combination enhances freshness and enriches the flavor.
We can often see that in the Dongting Lake area, with its dense water network and watery landscape, fishing and farming families often use water fish as an ingredient to make dishes mostly by boiling, braising, or steaming. They are fresh and natural, without excessive embellishment. In particular, "fisherman's dishes" and steam-pot stove preparations are full of rustic pastoral flavor. For example, braised water fish is first braised with various seasonings and then stewed in a steam-pot stove. The glossy red water fish meat, with its mellow and lingering fragrance, has already fallen off the bone and shed its spines, tender and richly fragrant, greatly stimulating the appetite. With such a delicacy in the world, why would one need to be an immortal in heaven?
Besides braising, water fish can also be steamed plain or stewed clear. If speaking of deliciousness, clear-stewed water fish naturally ranks first; but if speaking of difficulty in preparation, clear-stewed water fish is the most difficult of all. First, it must not be fried in oil; second, it must not be pan-fried in oil. Instead, one can only bring water to a rolling boil over high heat, then put in the freshly killed water fish, and after a little while, simmer it slowly over low heat. When it is 50 percent cooked, add pepper, and simmer slowly so the flavor enters; when it is 80 percent cooked, add a little salt. Salt and pepper must not be added too early or too late. If the salt is added too late, the flavor will not penetrate; if added too early, the meat becomes tough and not tender, and the soup becomes like clear water, lacking color, aroma, and taste. A master's water fish is excellent in color, aroma, and taste. The soup is clear without fishiness, mild yet lingering. It is especially suitable for those who have not eaten for a long time due to illness or have just recovered from a long illness, for the elderly, and for those who should not eat oily or meaty foods. After eating half a small bowl, the whole body feels comfortable and the appetite opens, so it is called "life-sustaining soup." This is the highest level of water fish preparation, and ordinary chefs do not dare to attempt it. Otherwise, it is either bland but so fishy it cannot be eaten, or not very fishy but tasteless. Clear-stewed water fish seems simple to make, using only pepper and salt, yet heat control and ingredients are very important. Like profound martial arts, killing may require only one or half a move, plain and unremarkable, yet this simplicity comes from complexity, and this clumsiness is born from skill.
The water fish is not only a delicious delicacy but also a highly nourishing tonic. In particular, the skirt edge of the water fish is especially delicious, rich but not greasy. Folk belief holds that the water fish is a precious tonic, and the skirt edge is the most precious of the precious. As for water fish blood and gallbladder, in Japan they are considered the best medicine for treating diabetes. According to analysis, the nutritional value of water fish blood can compare with that of the skirt edge. In our country's food culture, one major contribution to the world is dietary therapy. For thousands of years, this theory has not only been repeatedly explored and promoted domestically but has also influenced the Japanese archipelago, the Korean Peninsula, Southeast Asia, and many other countries and regions through cultural transmission. Traditional Chinese medicine theory holds that water fish meat is sweet in flavor and neutral in nature, and can "nourish yin, tonify deficiency, and regulate the middle." It has two major medicinal values: first, nourishing yin and clearing heat; second, reducing swelling and dissipating nodules.
Scientific research shows that the protein content in water fish muscle is as high as 15% to 18%, the amino acid content is as high as 19% to 43%, and the proportion of unsaturated fatty acids (UFA) is also very high, with an average of 75.43%, among which highly unsaturated fatty acids account for 32.39% of total fat, 6.54 times higher than beef, 2.85 times higher than pork, and 2.38 times higher than hairtail, far exceeding other foods. EPA and DHA originally have relatively high contents only in deep-sea fish, so it is extremely rare that water fish can have such high levels. The shell and meat of the water fish are also very rich in active phosphorus, calcium, iron, copper, manganese, zinc, selenium, and so on. Its blood, gallbladder, and meat also contain abundant vitamins, such as B1, B2, B6, B12, D, E, folic acid, pantothenic acid, and so on. This fully demonstrates that the nutritional value of water fish is so high that it cannot be matched by the meat of other animals. It is said that the Ma family army's display of prowess in Barcelona benefited from drinking water fish blood when thirsty and eating water fish meat when hungry. Therefore, it can be said that the water fish is a treasure house of nutrition and has been praised by Chinese and foreign scholars as the "source of life vitality."
The water fish can be said to be a treasure all over. Besides being eaten, it also has extremely high medicinal value. Its head, shell, bones, meat, eggs, gallbladder, and fat can all be used as medicine. According to modern pharmacological research, the water fish is rich in animal glue, keratin, vitamin T, and other substances essential to the human body. It has the effects of nourishing yin, tonifying qi, removing heat, treating malaria, reducing swelling and removing blood stasis, and softening hardness and dissipating nodules. When included in prescriptions, it has remarkable effects in treating tuberculosis. Water fish meat is sweet and neutral, and is also a good medicine in medicine, mainly treating heat and dampness. Veteran Chinese doctors say that eating water fish steamed with garlic and white pepper on the days of fu for three consecutive years can prevent or cure heatstroke-like illnesses. In addition, dried water fish head used as medicine can treat rectal prolapse, fistulas, and various childhood diseases. Water fish blood also has the same curative effects and can be used as a blood tonic, and can also treat infantile malnutrition; the back shell of the water fish has the effects of nourishing yin and supplementing yang, dissipating nodules, and calming the liver, and can treat cough, night sweats, kidney deficiency, amenorrhea, and other conditions; soft-shelled turtle gallbladder can treat high blood pressure; eggs can treat chronic diarrhea and chronic dysentery; water fish fat is a nourishing and strengthening medicine and can treat white hair. Using live water fish or water fish shell glue as raw materials, precious traditional Chinese medicines such as "Erlong Ointment," "Huisheng Dan," and "Water Fish Shell Steamed Decoction Pills" can be made.
Li Shizhen, a medical scientist of the Ming Dynasty, in his book Compendium of Materia Medica, called the soft-shelled turtle able to "replenish fatigue and damage, strengthen yang qi, and greatly tonify the insufficiency of yin qi," with effects such as "nourishing yin and clearing heat, calming the liver and subduing yang, and softening hardness and dissipating nodules." As far as the present stage is concerned, the tonic and strengthening effects of soft-shelled turtles rank first among all kinds of aquatic products. It is widely believed among our people that eating soft-shelled turtle regularly has the effect of preventing and treating many diseases, especially preventing and treating cancer, and this legend has now been confirmed by relevant scientific achievements. Modern medical research has further proved that the water fish can tonify the liver and kidney, nourish yin and strengthen yang, clear heat and purge fire, greatly tonify primordial qi, strengthen the spleen and stomach, strengthen tendons and bones, relieve fatigue, resist aging, and improve immune function, making people full of youthful vitality and able to adapt to the modern tense and busy rhythm of life. Therefore, preparations of water fish in Hong Kong and Taiwan regions of our country, as well as in Southeast Asia, Japan, and other places, are highly favored health products with enduring sales.
The latest research results show that marine shellfish, fish, and water fish all contain unsaturated fatty acids mainly composed of eicosapentaenoic acid and docosahexaenoic acid, all present in formed or unformed fats, and usually their nutritional value and function are not affected at high temperatures of around 100°C. When water fish is eaten steamed, braised, or made into soup, its nutritional value is not affected, but when the temperature reaches about 200°C, most or all of its nutritional value will be lost.
With the development of society today, the number one killer threatening people's lives is cardiovascular disease. As everyone knows, cardiovascular disease arises because the cholesterol content in the blood is too high, causing lipid masses to deposit on blood vessel walls, leading to vascular obstruction and hardening. Therefore, in evaluating a food, besides its nutritional value, another important aspect is that the lower the cholesterol content, the better. Among common meat foods, water fish belongs to those with low cholesterol content, and even among various marine and freshwater aquatic products, it still belongs to foods with low cholesterol content. According to a 1995 Japanese science and technology report: "The body of the water fish contains vitamin B17, especially with a very high content in the skirt edge." Vitamin B17 is an anticancer substance recognized by the World Health Organization (WHO). Therefore, regular consumption has the effect of strengthening the body and resisting cancer.
Because the water fish has extremely high nutritional value and also significant anticancer and cancer-preventing functions, it belongs to a super functional health food that is both medicine and food. Eating water fish is a relatively effective way to supplement the body, but it has shortcomings: first, supplementation is valuable for the long term, and truly improving the constitution is not a matter of one morning or one evening. It is difficult to ensure long-term and regular consumption of water fish, and also difficult to ensure the absorption quality of protein; second, when water fish is used in dishes, the blood, internal organs, and shell are generally discarded, yet these parts have the greatest medicinal value; moreover, household consumption of water fish requires high-temperature processing, and the active nutrients of the water fish will inevitably be damaged and lost when exposed to high temperatures.
Therefore, people's nutritional supplementation with water fish should no longer be limited only to cooking and eating it, but should rely on modern scientific and technological means to make it serve humanity more widely. Through extensive exploration, ultra-low-temperature and ultra-fine grinding technology is now used to bring water fish production into an industrial procedure, and in the production process there is no intervention of high temperature, acid, alkali, or enzymes, so that the nutritional substances and active ingredients of the water fish are fully retained. This overcomes the limitations of traditional edible and medicinal uses and opens up a new situation of whole-shell nourishment. These products are rich in protein and various unsaturated fatty acids and amino acids essential to the human body, are easy for the human body to absorb comprehensively, are suitable for long-term use, and have the dual effects of health preservation and auxiliary treatment. At present, tested by the Pharmacology Research Office of the School of Life Sciences at Sun Yat-sen University and appraised by experts from Sun Yat-sen University, South China University of Technology, Sun Yat-sen University of Medical Sciences, and other units, its development technology and production process have been recognized as reaching the advanced domestic level, with relatively significant effects in resisting fatigue and regulating the body's immune capacity. With the further development of science and technology and a deeper understanding of the water fish, the water fish will serve human health in a broader scope.