Extended data
nutritive value
Sweet potato tuber contains 60%-80% water, 10%-30% starch, about 5% sugar and a small amount of protein, oil, cellulose, hemicellulose, pectin and ash. If 2.5Kg fresh sweet potato is converted into 0.5Kg grain, its nutritional components are higher than rice and flour except fat.
Moreover, the composition of protein in sweet potato is reasonable, and the content of essential amino acids is high, especially lysine, which is relatively lacking in cereals, is high in sweet potato. In addition, sweet potato is rich in vitamins (carotene, vitamins A, B, C and E), and its starch is easily absorbed by the human body.
1, carotene
Vitamin A is known as "eye protection", which is transformed from carotene. Sweet potato is rich in carotene, which can provide rich vitamin A. The content of vitamin A can be as high as 40mg/ 100g of fresh sweet potato. Carotene can be converted into vitamin A after being absorbed by human body. Vitamin A can maintain normal visual function.
2. Edible fiber
The fiber content of sweet potato is 10 times of that of rice flour, which is fine in texture, does not harm the stomach, can accelerate the peristalsis of digestive tract, help defecation, clean digestive tract and shorten the retention time of toxic substances in food in intestine;
Reduce self-poisoning caused by constipation, reduce the concentration of carcinogens in the intestine, and prevent hemorrhoids and colorectal cancer. At the same time, cellulose can absorb some glucose, reduce the sugar content in blood, and help prevent diabetes.
3. The combination of sugar and protein
Sweet potato is rich in mucin, which is a mixture of polysaccharide and protein. It has a special protective effect on human body, and can keep the lubrication of digestive tract, respiratory tract, joint cavity and membrane cavity and the elasticity of blood vessels.
This substance can prevent arteriosclerosis caused by material deposition on arterial wall, prevent connective tissue atrophy of organs such as liver and kidney, slow down aging of human organs and improve immunity. Sweet potato also contains glycoprotein, which has good anti-mutation, hypolipidemic and immune enhancement effects.
4. Potassium
Sweet potato has high potassium content, which can alleviate the disadvantages caused by excessive salt intake. Potassium is also an important factor to protect the heart. Because potassium is an alkaline element, the pH value of sweet potato is 10. 1, which is a physiological alkaline food and has the function of neutralizing body fluids. Proper consumption of sweet potato is conducive to maintaining the acid-base balance of blood and to people's health, development and intellectual development.
Sweet potato is rich in protein, starch, pectin, cellulose, amino acids, vitamins and various minerals, and has the reputation of "longevity food". The sugar content reached 15%-20%. Has anticancer, heart protecting, emphysema and diabetes preventing, and weight reducing effects. Li Shizhen's Compendium of Materia Medica in Ming Dynasty recorded that "sweet potato can tonify deficiency, strengthen spleen and stimulate appetite, and strengthen kidney yin", and said that people in the sea can eat for a long time. Chinese medicine regards sweet potato as a good medicine.
Store and preserve
Before the first frost comes, sweet potatoes need to be dug out of the ground. Try not to damage its epidermis when digging, and store it in the previously dug cellar. The soil around the cellar is loess with a depth of 3-5 meters. Put the sweet potatoes neatly in the cellar, sprinkle some preservatives at last, and cover the cellar with a haystack.
1. After the temperature rises in spring, in calm and sunny weather, when the temperature exceeds 12℃ at noon, the concentration of miscellaneous bacteria in the cellar can be reduced, so as to prevent excessive humidity in the cellar from causing mildew on the damaged skin of potato pieces and affecting the appearance quality of goods.
2. The temperature in the cellar is always kept at113℃ and the relative humidity is kept at 85~90%. If the cellar temperature exceeds 15℃, properly open the vent to release the temperature.
However, it should be noted that the temperature in spring is often unstable, and there will be snowy and cold weather from some years to April. Especially in potato pits with poor thermal insulation performance, we must not be careless. Once the cellar temperature drops, immediately cover the vent for thermal insulation, and use heating facilities for proper heating if necessary.
3. When the humidity in the cellar is low, water should be added to the cellar pool or wet grass curtains should be laid on the walkway to increase the air humidity in the cellar.
Four, found that the sweet potato disease in the cellar has a spreading trend, should be taken out immediately and eaten as soon as possible, in order to reduce the loss of disease.
5. After the sweet potato seedlings are harvested in spring, it is planned to postpone storage. Attention should be paid to strengthening the management of temperature and humidity. The highest cellar temperature should not exceed 65438 05℃, and the relative humidity should be controlled at 65~90%. After the weather gets hot, we should also pay attention to the ventilation of the cellar.
For a long-term closed potato cellar with a large number of rotten potato pieces, the vent should be opened in advance for ventilation before entering the cellar, and it is safe to enter the cellar to avoid hypoxia and suffocation.
References:
Sweet potato. Baidu baike