Detailed Explanation of the Medicinal Value and Processing Methods of Turtle Plastron

1. Medicinal value of turtle plastron

Turtle plastron is slightly cold in nature, slightly salty in taste, and has a faint fishy odor. It contains gelatin, calcium salts, fat, keratin, and other substances. It has effects such as tonifying the heart and kidneys, nourishing yin and reducing fire, and subduing yang to relieve deficient heat. It is often made into turtle plastron glue, used for nourishing yin and subduing yang, tonifying the kidneys and strengthening the bones, enriching the blood and stopping bleeding, and for many conditions such as steaming bone tidal fever, flaccidity and weakness of the sinews and bones, dizziness and tinnitus, insomnia and forgetfulness, excessive menstruation, seminal emission, and night sweats. It is effective for lung disease, gastric bleeding, hypertension, cirrhosis, unnamed swellings and toxic lesions, and yin deficiency in women.

2. Processing method of turtle plastron glue

2.1 Quality standards

Raw turtle plastron with large plates, thick texture, and bright color is considered top grade, commonly known as blood plastron, and the Han plastron produced in the Dongting Lake area is especially the best. When held to the light and appearing transparent and pink, it is also called "blood slice," and is a precious product.

2.2 Method for preparing turtle plastron

2.2.1 Raw turtle plastron: Kill a live turtle, take its abdominal plate, remove the sinews and blood, wash it clean, and air-dry or sun-dry it to make blood plastron, which is of the best quality. Then soak the blood plastron in clear water, 20 d in summer and 40 d in winter, without changing the water, so that the skin, flesh, and fascia rot and separate easily from the turtle plastron; then take it out, wash it clean with clear water, and expose it to the sun by day and dew by night until it has no foul odor, at which point raw turtle plastron is obtained. If soaked in 6.5% sodium hydroxide solution, replacing the alkali solution once daily, the rotten flesh can be removed in 3-5 d, then taken out and sun-dried. In recent years, turtle plastron processed by the advanced yeast method is of very good quality and greatly shortens the processing time. The method is to first soak the turtle plastron in water at about 23°C for 2 d, pour off the water, add Candida yeast tank liquid amounting to 20%-30% of the weight of the turtle plastron, then add water to soak the turtle plastron and stir evenly and cover tightly; after 2 d white foam appears on the upper layer of the solution, and after another 10 d take it out and rinse it with water 5 times, then sun-dry until odorless to become raw turtle plastron.

2.2.2 Vinegar turtle plastron: Place sand in a pot and heat over high heat, add the washed raw turtle plastron, stir-fry until crisp in texture and pale yellow on the surface, then take it out, sift away the sand grains, put it into vinegar while hot and soak briefly, then take it out and air-dry or sun-dry. For 100 kg of turtle plastron, the amount of vinegar used is 20-25 kg.

2.3 Method for making turtle plastron glue

2.3.1 Raw material ratio: turtle plastron 10 kg, rock sugar 0.5 kg, yellow rice wine 0.3 kg, soybean oil 0.15 kg.

2.3.2 Preparation method: a) Decocting to obtain glue liquid: Place the processed turtle plastron in a copper pot, add water to submerge it, heat over gentle fire, keep at a slight boil for 1-2 d, then pour out the decoction; decoct 3-5 times in total until the glue liquid is fully extracted; b) Filtration and clarification: Combine the glue liquids from each decoction, filter to remove impurities, pass through a fine sieve, then filter with silk cotton, and add alum in portions while stirring evenly, let stand to settle, then filter again; c) Concentration and glue collection: Place the clarified glue liquid in a copper pot and heat over gentle fire to concentrate, stirring constantly to prevent scorching, until the glue liquid no longer passes through paper, then add the other weighed raw materials and mix evenly so that no oil droplets appear; when concentrated to the point of hanging in a flag, collect the glue and pour it into a gel basin to cool and solidify naturally. To speed up solidification, 5%-10% donkey-hide gelatin may be added; d) Slicing and packaging: Take out the solidified glue block and cut it into small slices with a knife, air-dry, and package in fixed amounts for sale.

2.3.3 Quality specifications: Turtle glue color: brownish green, semi-transparent. Specifications: length 3 cm, width 3 cm, thickness 1 cm, each piece weighing about 5 g.