Nutritional value characteristics of vegetables: In China, there are many kinds of vegetables, with more than 200 varieties planted, which are rich in phytochemicals and are important sources of micronutrients, dietary fiber and natural antioxidants. So what are the characteristics of the nutritional value of vegetables?

Nutritional value characteristics of vegetables 1 Vegetables are rich in water, low energy and phytochemicals, and are important sources of micronutrients, dietary fiber and natural antioxidants.

Generally, the water content of fresh vegetables is 65% ~ 95%, and the water content of most vegetables is above 90%.

Vegetables contain cellulose, hemicellulose, pectin, starch and carbohydrates, and most of them have low energy [209 kJ (50 kcal)/100 g], so vegetables are a low-energy food. Vegetables are good sources of carotene, vitamin B2, vitamin C, folic acid, calcium, phosphorus, potassium and iron.

Each vegetable has its own nutritional characteristics.

Young stems, leaves and cauliflower vegetables (such as Chinese cabbage, spinach and broccoli) are good sources of carotene, vitamin C, vitamin B2, minerals and dietary fiber. Vitamin C is abundant in the leaves, flowers and stems of plants with vigorous metabolism, which is parallel to the distribution of chlorophyll. Generally, the contents of carotene, riboflavin and vitamin C in dark vegetables are higher than those in light vegetables and contain more phytochemicals. The vitamin content in the leaves of the same vegetable is generally higher than that in the roots, such as lettuce leaves, celery leaves and radish tassels, which is several times higher than that in the roots of the corresponding stems. The nutritional value of leafy vegetables is generally higher than that of melon vegetables. The dietary fiber of root vegetables is lower than that of leafy vegetables. Cruciferae vegetables (such as cabbage, cauliflower, cabbage, etc.). ) contains phytochemicals such as aromatic isothiocyanate, which is the main anticancer component in the form of glycoside. The content of carbohydrates such as water chestnut and lotus root in aquatic vegetables is high. Bacteria and algae (such as Tricholoma, Lentinus edodes, auricularia auricula, yeast, laver, etc.). ) contains minerals such as protein, polysaccharide, carotene, iron, zinc and selenium, and is also rich in iodine in marine bacteria and algae (such as laver and kelp).

2. What are dark vegetables?

Vegetables can be divided into dark vegetables and light vegetables according to color depth, and the nutritional value of dark vegetables is generally better than light vegetables. Dark vegetables refer to dark green, red, orange and purplish red vegetables, which are rich in carotene, especially β-carotene, and are the main source of vitamin A for Chinese residents. In addition, dark vegetables also contain many other pigments, such as chlorophyll, lutein, lycopene, anthocyanin and so on, as well as aromatic substances, which give vegetables special rich color, fragrance and taste, promote appetite and present some special physiological activities.

Common dark green vegetables: spinach, rape, cold winter vegetables, celery leaves, water spinach (water spinach), lettuce leaves, mustard greens, broccoli, watercress, shallots, chrysanthemum morifolium, leeks, radish sprouts, etc.

Common red and orange vegetables: tomatoes, carrots, pumpkins, red peppers, etc.

Common purplish red vegetables: red amaranth, purple cabbage, water shield and so on.

Step 3 choose vegetables carefully

There are many kinds of vegetables, and the nutritional value of different vegetables varies greatly. Only by choosing a reasonable combination of different varieties of vegetables can it be beneficial to your health. It is recommended to consume 300 g ~ 500 g of various vegetables every day. First of all, encourage the choice of fresh seasonal vegetables to avoid losing some nutrients due to long storage time. In addition, if conditions permit, try to choose a variety of vegetables to eat. In view of the nutritional advantages of dark vegetables, special attention should be paid to the intake of dark vegetables to make them account for half of the total intake of vegetables, and attention should also be paid to increasing the intake of cruciferous vegetables, bacteria and algae. Pickled vegetables and pickles contain more salt and vitamins, so eat less. When eating vegetables with more starch, such as potatoes, taro, lotus root and yam, we should appropriately reduce the staple food to avoid excessive energy intake.

4. How to cook vegetables reasonably

The nutritional value of vegetables is not only influenced by varieties, parts, producing areas, seasons and other factors, but also by cooking methods. Heating cooking will reduce the nutritional value of vegetables, and edible vegetables such as tomatoes, cucumbers and lettuce should be washed before eating. The correct way to cook vegetables is:

Wash before cutting: the correct way is to rinse with running water, wash before cutting, and don't soak vegetables in water for too long. Otherwise, too much water-soluble vitamins and inorganic salts in vegetables will be lost.

Quick fry: the carotene content is relatively high.

Frying high green leafy vegetables with oil can not only reduce the loss of vitamins, but also promote the absorption of carotene.

Serve the soup: the vitamin C content is high.

Vegetables suitable for raw food should be eaten as cold as possible, or boiled in boiling water 1 ~ 2 minutes before mixing, or cooked with hot soup and oil. Boiling root vegetables with boiling water can soften dietary fiber and improve the taste of vegetables.

Cooking is ready to eat: the cooked dishes should be eaten as soon as possible, with soup and vegetables; Do it now to avoid repeated heating, not only because nutrients will be lost with storage time. It is also possible to increase nitrite content due to nitrate reduction of bacteria.

5. Nutritional characteristics of fruits

Most fresh fruits contain 85% ~ 90% water, which is an important source of vitamins (vitamin C, carotene and B vitamins), minerals (potassium, magnesium and calcium) and dietary fiber (cellulose, hemicellulose and pectin) in the diet. Red and yellow fruits (such as mango, citrus, papaya, hawthorn, seabuckthorn, apricot and Rosa roxburghii) have high carotene content; Jujube (fresh jujube, wild jujube), citrus (orange, mandarin orange, pomelo) and berry (kiwi fruit, seabuckthorn, blackcurrant, strawberry and Rosa roxburghii) have higher vitamin C content. Banana, blackcurrant, jujube, red fruit and longan have higher potassium content. Mature fruits generally contain more nutrients than immature fruits.

Fruits contain more carbohydrates than vegetables, mainly in the form of disaccharides or monosaccharides. For example, apples and pears are mainly fructose, and grapes and strawberries are mainly glucose and fructose. If the content of organic acids such as acid, citric acid, malic acid and tartaric acid in fruits is richer than that in vegetables, it can stimulate the secretion of digestive glands, stimulate appetite and help reduce food consumption. At the same time, organic acids can protect the stability of vitamin C, and fruits are rich in dietary fiber, which can promote intestinal peristalsis. In particular, fruits contain more pectin. This soluble dietary fiber can reduce cholesterol and prevent atherosclerosis. It can also combine with harmful substances such as lead in the intestine to promote its excretion. In addition, fruits also contain phytochemicals such as flavonoids, aromatic substances, coumarin and D- limonene (in the oil of peel), which have special biological activities and are beneficial to human health.

6. Vegetables and fruits cannot replace each other.

Although vegetables and fruits have many similarities in nutritional components and health care effects, they are two different foods after all, and their nutritional values also have their own characteristics. Generally speaking, there are far more varieties of vegetables than fruits, and the contents of vitamins, minerals, dietary fiber and phytochemicals in most vegetables (especially dark vegetables) are higher than those in fruits, so fruits cannot replace vegetables. In diet, fruit can supplement the deficiency of vegetable intake. There are more carbohydrates, organic acids and aromatic substances in fruits than fresh vegetables, and fruits do not need to be heated before eating, and their nutrients are not affected by cooking factors, so vegetables cannot replace fruits. It is recommended to eat vegetables every meal and fruits every day.

7. Don't replace fresh fruit with processed fruit products.

Because fresh fruits are generally difficult to preserve for a long time, and it is troublesome to carry and ingest, people have invented various methods to process fruits into products to prolong the shelf life and facilitate eating. Common fruit processed foods include fruit juice, canned fruit, preserved fruit and so on. Fruit juice is made by squeezing the fruit to remove the residue. However, these processing processes will cause the loss of vitamin C, dietary fiber and other nutrients in fruits to a certain extent. Preserved fruit is made of fresh fruit with sugar stains, which has more vitamin loss and higher sugar content. Dried fruit is dehydrated from fresh fruit, which leads to more vitamin loss. Therefore, fruit products can't replace fresh fruits. Try to choose fresh fruits. However, in the case of inconvenient carrying and intake, or insufficient fruit intake, fruit products can be used to supplement.

8. Dietary fiber is an essential dietary component for human body.

Although dietary fiber can't be digested and absorbed, it plays an important physiological role in the body and is very important for maintaining human health. The 26th session of Codex Alimentarius Commission in 2004 pointed out that dietary fiber has at least the following physiological functions: increasing fecal volume, softening feces, stimulating colon fermentation, lowering blood total cholesterol and/or low-density cholesterol levels, and lowering postprandial blood glucose and/or insulin. Therefore, dietary fiber can prevent constipation, dyslipidemia and diabetes, which is beneficial to intestinal health.

Dietary fiber is rich in plant foods, 3% in vegetables and 2% in fruits. Due to different processing methods, edible parts and varieties, dietary fiber content is also different. Carrots, celery, shepherd's purse, spinach and leeks are higher than tomatoes and eggplant, while pineapples, strawberries and water chestnuts are higher than bananas and apples. The content of dietary fiber in the edge epidermis or peel of the same vegetable or fruit is higher than that in the center. If you remove it when eating, you will lose some dietary fiber. Therefore, when people eat unpolluted vegetables and fruits, they should try to eat the peel and pulp together. It is recommended that normal adults consume 25g~30g dietary fiber every day.

9. What are the nutritional characteristics of potatoes?

Common potatoes are sweet potatoes (also known as sweet potatoes, sweet potatoes, sweet potatoes, sweet potatoes and so on. ), potato (also known as potato, potato), cassava (also known as tree potato, wood sweet potato), taro potato (taro, yam).

The protein content of sweet potato is generally 1, 5%, the amino acid composition is similar to that of rice, the fat content is only 0,2%, and the carbohydrate content is as high as 25%. The content of carotene, vitamin B 1, vitamin B2, vitamin C and nicotinic acid in sweet potato is higher than that in cereal, and the content of carotene in red sweet potato is higher than that in white sweet potato. Sweet potato has high dietary fiber content, which can promote gastrointestinal peristalsis and prevent constipation.

Potatoes are widely planted in China, and as the representative of potato food, they are deeply loved by the public. Potato contains starch 17% and is rich in vitamin c and potassium, which can be used as both staple food and vegetable.

Cassava contains more starch, but protein and other nutrients are low, so it is an excellent raw material for starch production. All parts of cassava plants contain hydrocyanic acid, which must be detoxified before eating.

The starch content in dried potato can reach about 80%, while the protein content is only about 5%, and the fat content is about 0 and 5%, so it has the functions of controlling weight and preventing constipation.

Because the protein content of potatoes is low, children eat too much for a long time, which is not good for growth and development.

10, how to eat potatoes?

In recent 20 years, China residents' potato intake has obviously decreased. The average daily potato intake of urban and rural residents in China was 1982, which decreased to 49 1g in 2002. It is suggested to increase the potato intake appropriately, about 50g ~ 100g each time, five times a week. Potatoes are best steamed, boiled and baked to retain more nutrients. Use frying as little as possible to reduce the content of oil and salt in food.

Nutritional value characteristics of vegetables 2 Fresh vegetables are the most important part of our balanced diet and one of the important characteristics of our traditional diet. Vegetables are important sources of vitamins, minerals, dietary fiber and phytochemicals, with high water content and low energy. A diet rich in vegetables and fruits plays an important role in keeping healthy, maintaining normal intestinal function, improving immunity and reducing the risk of chronic diseases such as obesity, diabetes and hypertension. Therefore, in recent years, dietary guidelines in various countries have emphasized increasing the variety and quantity of vegetables and fruits. It is suggested that we adults eat 300g~500g vegetables every day, preferably about half of them are dark vegetables.

Vegetables are rich in water, low energy and phytochemicals, and are important sources of micronutrients, dietary fiber and natural antioxidants. Generally, the water content of fresh vegetables is 65%~95%, and the water content of most vegetables is above 90%. Vegetables contain cellulose, hemicellulose, pectin, starch, carbohydrates and so on. And most of them are low-energy, so vegetables are a low-energy food. Vegetables are good sources of carotene, vitamin B2, vitamin C, folic acid, calcium, phosphorus, potassium and iron.

Each vegetable has its own nutritional characteristics. Young stems, leaves and cauliflower vegetables (such as Chinese cabbage, spinach and broccoli) are good sources of carotene, vitamin C, vitamin B2, minerals and dietary fiber. Vitamin C is abundant in the leaves, flowers and stems of plants with vigorous metabolism, which is parallel to the distribution of chlorophyll. Generally, the contents of carotene, riboflavin and vitamin C in dark vegetables are higher than those in light vegetables, and they contain more plant compounds. The vitamin content in the leaves of the same vegetable is generally higher than that in the roots, such as lettuce leaves, celery leaves, radish tassels, etc., which are several times higher than the corresponding neck roots. The nutritional value of leafy vegetables is generally higher than that of melon vegetables. The dietary fiber of root vegetables is lower than that of leafy vegetables. Cruciferae vegetables (such as cabbage, cauliflower, cabbage, etc.). ) contains phytochemicals such as aromatic isothiocyanate, which is the main anticancer component in the form of glycoside. The content of carbohydrates such as water chestnut and lotus root in aquatic vegetables is high. Bacteria and algae (such as mushrooms, fungus, yeast, laver, etc. ) contains minerals such as protein, polysaccharide, carotene, iron and zinc, and is also rich in iodine in marine bacteria and algae (such as laver and kelp).

Nutritional value characteristics of vegetables 3 1, vegetables

Nutritional characteristics of vegetables: Vegetables are rich in water and low in energy, and are important sources of micronutrients, dietary fiber and natural antioxidants. Generally, the water content of fresh vegetables is 80%~95%, and most of them are above 90%. Vegetables contain cellulose, hemicellulose, pectin, starch, sugar and so on, and most of them have low energy. Vegetables are also good sources of carotene, vitamin B2, vitamin C, folic acid, calcium, phosphorus, potassium and iron.

Vegetables can be divided into dark vegetables and light vegetables, and the nutritional value of dark vegetables is generally better than light vegetables. Dark vegetables refer to dark green, red, orange and purplish red vegetables. It is rich in carotene, especially β-carotene, which is the main source of vitamin A. Dark vegetables also contain a variety of pigments, such as chlorophyll, lycopene, anthocyanins and other aromatic substances. They give vegetables special color, taste and fragrance, which can stimulate appetite.

Common dark green vegetables such as spinach, rape, celery, broccoli, chrysanthemum, leek and so on.

Common red and orange vegetables, such as tomatoes, carrots, pumpkins and red peppers.

Common purplish red vegetables such as purple cabbage and red amaranth.

2. Fruit

Nutritional characteristics of fruits: Most fresh fruits contain 85%~90% water. It is an important source of vitamins, minerals and dietary fiber in diet. Red and yellow fruits, such as mango, papaya, hawthorn, apricot and so on. Its carotene content is high; Jujube, citrus and berries, such as kiwi fruit, blackcurrant and strawberry, have higher vitamin C content. Banana, longan and jujube have higher potassium content. Mature fruits generally contain more nutrients than immature fruits.

Although vegetables and fruits have many similarities in nutrients and health effects. But after all, they are two different foods with different nutritional values. Generally speaking, there are far more varieties of vegetables than fruits, and the contents of vitamins, minerals, dietary fiber and phytochemicals in most vegetables, especially dark vegetables, are higher than those in fruits. So fruits can't replace vegetables.

Fruit can supplement the deficiency of vegetable intake in diet. There are more sugars, organic acids and aromatic substances in fruits than in fresh vegetables. Moreover, fruits do not need to be heated before eating, and their nutrients are not affected by cooking factors, so vegetables cannot replace fruits.

Step 3: potatoes

Nutritional characteristics of potatoes: The protein content of potatoes is generally 1, 5%, the amino acid composition is similar to that of japonica rice, and the fat content is only 0,2%. The sugar content is as high as 25%. The content of carotene, B vitamins, vitamin C and nicotinic acid in potatoes is higher than that in cereals. The content of dietary fiber in sweet potato is high, which can promote gastrointestinal peristalsis and prevent constipation.

4. milk

Milk is a kind of natural food with complete nutrients, appropriate proportion of ingredients, easy digestion and absorption and high nutritional value. Can provide high-quality protein, vitamin A, vitamin B and calcium. The average content of protein in milk is 3%, and the digestibility is over 90%. The proportion of essential amino acids also meets the needs of human body and belongs to high-quality protein. The fat content is 3%~4%, which exists in the form of micro-fat globules, which is beneficial to digestion and absorption. Sugar is mainly lactic acid, which has the functions of regulating gastric acid, promoting gastrointestinal peristalsis and promoting the secretion of digestive juice. It can also promote the absorption of minerals such as calcium, iron and zinc. To promote the proliferation of intestinal lactic acid bacteria and inhibit the growth of spoilage bacteria. Milk is rich in calcium, phosphorus and potassium, which is easily absorbed by human body and is the best source of calcium in diet.