There are many kinds of vegetables, which can be divided into fresh beans, roots, tender stems, leaves, moss, flowers, melons, eggplant fruits, fungi and algae according to the edible parts. There are great differences in nutritional composition and nutritional value among varieties. Scientists divide vegetables into four categories according to their nutrient contents: A, B, C and D-A vegetables are rich in carotene, riboflavin, vitamin C, calcium and fiber. , with high nutritional value, mainly including Chinese cabbage, spinach, mustard, amaranth, leek, sherry red and so on. -B vegetables are not as nutritious as A vegetables, and they are usually divided into three types. The first one contains riboflavin, including all fresh beans and bean sprouts; The second category contains more carotene and vitamin C, including carrots, celery, green onions, green garlic, tomatoes, peppers and sweet potatoes. The third category mainly contains vitamin C, including Chinese cabbage, cabbage and cauliflower. -C vegetables are low in vitamins but high in calories, including potatoes, yams, taro, pumpkins, etc. -D Vegetables contain a small amount of vitamin C and have low nutritional value, such as wax gourd, bamboo shoots, eggplant and water bamboo.

Vegetable nutrition collocation Vegetables have different nutritional components and contents in different parts of the same vegetable due to different edible parts, different colors and different growth periods. Vegetables can be divided into three categories: stem and leaf, root tuber and fruit, as well as cauliflower and melon.

Stem and leaf vegetables include rape, leek, Chinese cabbage, spinach and so on.

Generally rich in vitamin C and carotene. Spinach contains iron, but it also contains a lot of oxalic acid, which will hinder the absorption of calcium and iron in food. Therefore, before cooking spinach, you should blanch it in boiling water to remove some oxalic acid, and it is best not to eat too much spinach at a time to avoid diarrhea. Root vegetables include radish, carrot, taro, potato and sweet potato. Radish contains a lot of vitamin C, carrot contains a lot of carotene, sweet potato contains both vitamin C and carotene, potatoes and taro contain more starch, higher calories and less other nutrients. Root vegetables have the same feature that they are rich in crude fiber. If radish and carrot are cut into thin slices or thin strips and left for 1 ~ 2 days, their crude fiber can be increased by about 3 times. Therefore, radish food should be eaten now, and it is not suitable for storage after cutting. Fruits and vegetables include tomatoes, beans, sweet peppers, cucumbers, loofah, pumpkins and eggplant. Except beans, pumpkins, loofah and eggplant, these vegetables should be eaten raw to avoid the destruction of vitamins during cooking. Tomatoes contain more lycopene and vitamin C, and beans include lentils, peas and edamame. The content of protein is higher, with more amino acids than grains, and other vegetables such as calcium, phosphorus, iron and vitamin b 1 are also higher than other vegetables. Pumpkin contains a lot of carotene. Pepper is rich in carotene and vitamin C, and the nutritional components of different parts of the same vegetable are also different. For example, the nutrients in the green part of green onions are much higher than those in the white part. The contents of vitamin A, vitamin b 1 and vitamin C in green onions are less than half of those in green onions. The dark green leaves of the same celery plant contain more vitamin A and vitamin C than the light green stems and culms. There is also Chinese cabbage. Leaves are more nutritious than stems. The nutritional value of vegetables is closely related to the color of vegetables. Dark color has high nutritional value, while light color has low nutritional value. The order of arrangement is "green vegetables → yellow and red vegetables → colorless vegetables". Similar vegetables have different nutritional values because of their different colors. Purple eggplant is rich in vitamin P, which can increase the pressure resistance of microvascular wall and improve vascular function, and is quite beneficial to patients with hypertension, cutaneous purpura and bleeding tendency. The nutritional value of yellow carrot is higher than that of red carrot. It contains not only a lot of carotene, but also lutein, which has a strong anti-cancer effect. Different parts of the same vegetable have different nutritional values because of different colors. The nutritional value of green onions is much higher than that of white onions. The contents of vitamin B 1 and vitamin C per 100g of scallion are less than half of that of scallion. Green celery leaves contain 6 times more carotene and 4 times more vitamin D than light celery leaves and stems. In addition, because each vegetable contains different types and quantities of nutrients, the nutritional needs of the human body are also different, so when choosing vegetables, we should pay attention to different varieties of vegetables and their nutritional values:

Classification of vegetable characteristics of vegetable varieties

Class A Vegetables All green vegetables and wild vegetables, such as small ones, are rich in vitamin C and vitamin B2.

Chinese cabbage, rape, spinach, amaranth, carotene, calcium.

Water spinach, mustard greens, radish tassels, bowls

Bean sprouts, sweet potato leaves, boiled vegetables, etc.

Vegetables All fresh beans and soybean sprouts are rich in vitamin B2.

Carrots, green onions, green garlic and celery

Tomatoes, peppers, pumpkins. Rich in vitamin c and carrots.

Chinese cabbage, cabbage and cauliflower are rich in vitamin C and calcium.

Class C vegetables, such as potatoes, yams, taro, arrowheads, etc., contain a small amount of vitamins and more starch.

High calorie.

Vegetables and fruits such as roots, melons and eggplants contain a small amount of vitamin C, vitamin B2 and carrots.

In addition to the color depth, we should also consider a variety of vegetables and eat vegetables and meat together.

The colors of vegetables and nutritious vegetables are mainly green, red, yellow, purple and black. Different colors of vegetables contain different nutrients and quantities, which have different maintenance effects on human health. People eat the most green vegetables in their daily lives. The greener and fresher the color, the richer vitamins C and B, and the more mineral elements such as calcium, potassium, sodium and magnesium. Green vegetables are the best sources of trace elements such as iron, copper, iodine, cobalt, molybdenum, selenium and germanium. Dark green algae are called longevity vegetables. Vitamin C, which is rich in green vegetables, can promote the regeneration of liver cells and the synthesis of liver sugar, enhance the detoxification ability of liver, keep the elasticity of blood vessel wall and reduce cholesterol in blood. Red-based vegetables include red carrots, tomatoes, amaranth, etc., which can enhance human resistance. For example, carrots contain protein, fat, sugar, calcium, phosphorus, iron, boron, vitamins, carotene, hyaluronic acid, potassium salt and so on. Modern science has proved that carrots can enhance coronary blood flow, reduce blood fat, lower blood pressure, resist cancer, and also have the functions of anti-aging and promoting the intellectual development of infants. Yellow-based vegetables include day lilies (day lilies), yellow carrots, leeks and golden melons. They contain vitamin e and lutein. Vitamin E can inhibit the production of lipid peroxide, reduce its toxicity, protect and regulate the normal physiological functions of organs and blood vessel walls, thus slowing down human aging and reducing pigmentation. Vegetables dominated by purple, such as perilla, purple lentils, seaweed, etc., have high nutritional value, can also regulate nerve function and increase the secretion of gastrin, and have been regarded as treasures of dietotherapy since ancient times. Black-based vegetables are: Nostoc flagelliforme, black mushrooms, black sesame and so on. Auricularia auricula is rich in protein and vitamins, and its iron content is the highest among all kinds of edible fungi, which has a good effect on preventing and treating anemia, coronary heart disease and relieving coronary atherosclerosis. Now there is a "Kuroshio" diet fever in Europe and America, and black food is favored.

Vegetables are an important supplementary food, which is in great demand and has many kinds every day. It is an indispensable food for regulating and improving life. Vegetables are an important source of vitamin C, carotene and vitamin B2 in the diet. Among them, vitamin C and carotene are relatively lacking in other foods. If you lack fresh vegetables for a long time, it is easy to suffer from vitamin deficiency. Vegetables are rich in minerals, besides calcium, phosphorus and iron, they also contain more potassium, sodium and magnesium. The final products of metabolism of these ingredients in human body are alkaline, so vegetables are also called alkaline food. Mixing vegetables with acidic foods rich in protein, such as grains, beans, meat, fish, etc., and keeping a certain proportion will help the human body maintain acid-base balance. Vegetables also contain protein and sugar, although the proportion is not large, but a large number of edible, can replace part of the grain. Crude fiber in vegetables can stimulate gastrointestinal peristalsis, maintain normal digestive function and reduce the harm of toxic substances to human body. Some vegetables also contain volatile aromatic oils, organic acids and some special ingredients, which have the functions of seasoning, deodorization and sterilization, can promote appetite and help digestion, and are also important condiments.

There are many kinds of vegetables, which can be divided into:

1. leafy vegetables: such as Chinese cabbage, rape, spinach, amaranth, Chinese cabbage, cabbage, leek, sherry red, etc.

2. Root vegetables: such as lettuce, kohlrabi, water bamboo, potato, onion, arrowhead, taro, lotus root, carrot and so on.

3. Fruits and vegetables: such as eggplant, pepper, tomato, cucumber, pumpkin, wax gourd, bitter gourd, green beans, tender broad beans, lentils and edamame.

4, cauliflower: such as cauliflower, day lily and so on.

Leafy vegetables, especially leafy vegetables, are rich in vitamin C and carotene. Carotene is a kind of yellow pigment, which is rich in yellow vegetables. Except for fresh varieties, most root vegetables contain more carbohydrates.

Peppers and tomatoes in fruits and vegetables contain more vitamins, while melons and vegetables generally have lower nutritional value. Beans and vegetables contain more protein and vitamin B2.

Vegetables grow in season. In the peak season of production, the variety is complete and the quantity is large. As long as we pay attention to adjusting the pattern, the demand for vitamin C and carotene can be completely guaranteed. In the off-season of vegetables, we should pay attention to eating a certain amount of green leafy vegetables as much as possible and eating less melon vegetables.

There are many kinds of wild vegetables, which can be seen everywhere. Although most of them are bitter, they are rich in vitamins and minerals, especially

There are many wild vegetables with much more vitamin C and carotene than ordinary vegetables. When collecting wild vegetables, we must pay attention to prevent poisoning. For bitter wild vegetables, you can first blanch them in boiling water for one minute, and then soak them in clear water to remove the bitterness.

Different varieties of vegetables have different nutritional values;

Classification of vegetable characteristics of vegetable varieties

Class A Vegetables All green vegetables and wild vegetables, such as small ones, are rich in vitamin C and vitamin B2.

Chinese cabbage, rape, spinach, amaranth, carotene, calcium.

Water spinach, mustard greens, radish tassels, bowls

Bean sprouts, sweet potato leaves, boiled vegetables, etc.

Vegetables All fresh beans and soybean sprouts are rich in vitamin B2.

Carrots, green onions, green garlic and celery

Tomatoes, peppers, pumpkins. Rich in vitamin c and carrots.

Chinese cabbage, cabbage and cauliflower are rich in vitamin C and calcium.

Class C vegetables, such as potatoes, yams, taro, arrowheads, etc., contain a small amount of vitamins and more starch.

High calorie.

D The roots of vegetables, melons and fruits such as eggplant contain vitamin C and vitamin B2, and the colors of vegetables can be divided into four types: green, purple, yellow and nearly white. After analyzing the nutritional components of various vegetables, scientists found that dark vegetables have high nutritional components, while light vegetables have low nutritional components. Their order is green (dark green has the highest chlorophyll content), reddish purple, yellow and white. Green vegetables include mustard, rape, green vegetables, amaranth, spinach, celery and so on. Red and purple vegetables are purple cabbage imported from Europe. In China, there are red cabbage moss, purple lentils and eggplant. Yellow vegetables include tomatoes, carrots, sweet potatoes and cabbage. Colorless vegetables include white gourd, white gourd, bamboo shoots, water bamboo, cauliflower and so on. The best way to eat green vegetables is dark green vegetables with plenty of sunshine. Scientists have found that the nutritional value and health care efficacy of the same green vegetables often vary with the degree of sunshine. Vitamins and interferon inducers in vegetables have the weakness of "fear of heat", and high-temperature cooking will destroy them, so it is best to eat fresh vegetables, and it is best to eat them raw. Because the human body needs "all-round" nutrition, it is impossible to meet this requirement simply by eating any kind of vegetables, so only by reasonable and ingenious collocation and adhering to multiple varieties and colors can we ensure a balanced nutrition.

(3) Vitamin C: All fresh vegetables contain vitamin C, especially Chinese cabbage, Chinese cabbage, rape, amaranth, bell pepper, tomato and bitter gourd.

Leafy vegetables contain more inorganic substances and vitamins than other roots, melons and fruits, so you should eat more leafy vegetables.

The relationship between cooking and nutritional value: vegetables will lose some vitamins after cooking, and the amount depends on the cooking method of vegetables. The most loss is vitamin C, followed by vitamin B, and the least loss is carrot. In order to reduce the loss of inorganic substances and vitamins in vegetables, we should pay attention to the following points:

1, the skin of a vegetable or the pod of a bean head, etc. , which must be removed before use.

2, vegetables should be washed first and then cut. Don't soak in water for a long time when washing, and don't cut too much to reduce the loss of vitamins.

3, do not use copper utensils, do not add alkali.

4, the time for cooking soup should be short. When cooking soup, it is advisable to boil the soup first, and then add vegetables.

5. Because some vitamins can be dissolved in water, it is necessary to add less water when cooking and eating vegetable soup, especially to correct the bad cooking method of squeezing out vegetable juice.

6. Vegetables should be eaten immediately after cooking, so as to reduce the time in the middle.

Second, fruit.

The nutritional composition and value of fruits are similar to those of fresh vegetables.

1, calories: from protein: the protein content of fresh fruits is also low, with an average of less than 1 00g.

3. Inorganic salts: Fresh fruits seem to be a good source of inorganic salts such as calcium, phosphorus, iron, copper and manganese; Dried fruit contains more ingredients than fresh fruit. Among them, red fruits, oranges and strawberries have slightly higher calcium content, while grapes, dates, red fruits, bananas, apricots, strawberries and cherries have slightly higher iron content.

4. vitamins:

(1) Carrot glucosinolate: Red and yellow fruits such as orange, red fruit, cherry and pineapple are rich in this element.

(2) B vitamins: Only dried fruits contain more B vitamins.

(3) Vitamin C: Fresh fruits are rich sources of vitamin C, among which fresh dates, red fruits, oranges, lemons, grapefruit and strawberries are the most abundant. Generally speaking, the peel contains more than the pulp. Sugar contained in & ltBR & ltp>, such as sugar, sucrose and starch. , not too much. In addition to inorganic salts and vitamins, fruits also supply organic acids and cellulose. The former can stimulate gastric juice and the latter can promote intestinal peristalsis.

1. Carbohydrate

Carbohydrates contained in vegetables include starch, sugar, cellulose and pectin. Root vegetables contain more starch, such as potatoes, yams, arrowheads and sweet potatoes. The carbohydrate content can reach 10% ~ 25%. Potatoes occupy a certain proportion in people's diet in some areas and become one of the important sources of human heat energy. The content of starch in general vegetables is only 2% ~ 3%; Some sweet vegetables contain a small amount of sugar, such as carrots, tomatoes and sweet potatoes.

Vegetables are an important source of dietary fiber (cellulose, hemicellulose and pectin). Leaves and stems contain more cellulose and hemicellulose, while pumpkins, carrots and tomatoes contain a certain amount of pectin.

2. Inorganic salts and trace elements

Vegetables contain some inorganic salts needed by human body, especially sodium, potassium, calcium, magnesium, iron, phosphorus and fluorine. It can not only supplement the needs of human body, but also play an important role in the acid-base balance of the body. Vegetables also contain a certain amount of trace elements, such as copper, zinc, iodine and molybdenum. Among them, the vegetables containing more calcium mainly include cowpea, spinach, water spinach, winter amaranth, coriander, potato, alfalfa, celery, leek and tender peas. Vegetables with high iron content mainly include day lily, shepherd's purse, celery, water chestnut, water chestnut, Chinese cabbage and other green leafy vegetables. Vegetables containing sodium mainly include celery, Malantou, pickled mustard tuber and chrysanthemum morifolium. Vegetables containing more potassium mainly include fresh bean vegetables, peppers, pickled mustard tuber, sliced mushrooms, fragrant shavings and so on. Vegetables containing more copper include taro, spinach, eggplant, fennel, shepherd's purse, onion and Chinese cabbage. Vegetables with relatively high zinc content include Chinese cabbage, radish, eggplant, pumpkin and potato. However, although most vegetables contain more inorganic salts and trace elements, they also contain higher oxalic acid and dietary fiber, which affects the digestion and absorption of inorganic salts and trace elements and has low nutritional value. Vegetables with high oxalic acid content mainly include spinach, cowhide, water spinach, fresh bamboo shoots and onions.

vitamin

Vegetables are rich in vitamins, the most important of which are vitamin C and carotene. The contents of vitamin A and vitamin D in vegetables are not high.

Vitamin C is mainly distributed in leaves, flowers, stems and other tissues and organs with strong metabolism, which is parallel to chlorophyll distribution. The content of green pepper, cauliflower and potherb mustard is relatively high, such as144 mg (100g)-1for green pepper and 72 mg (/kloc-0 for persimmon pepper. Cauliflower 61mg (100g)-1,potherb 52mg( 100g)-1, rape 36mg( 100g)-1. Compared with leafy vegetables, the content of vitamin C in most melons and root vegetables is not high, such as cucumbers and tomatoes, but the utilization rate is relatively high because they can be eaten raw and will not be destroyed by the cooking process.

Carotene coexists with other pigments in vegetables. All green, red, orange and purple vegetables contain carotene, especially dark leafy vegetables, such as leek, rape, spinach, amaranth and lettuce leaves, and the content can be as high as 2mg per 100g vegetable.

Vegetables contain flavonoids, among which bioflavonoids belong to vitamins, which are similar to ascorbic acid and have antioxidant effects, which can protect vitamin C in vegetables from damage, and vitamin E and retinol also have antioxidant effects. Bioflavonoids are abundant in green pepper, cabbage, garlic, onion and tomato.

4. protein, fat

The content of protein in vegetables is very low, about 1% ~ 3%. Amino acid composition does not meet the needs of human body, and contains no or only a small amount of fat.

5. Aromatic substances, pigments and enzymes

Vegetables contain a variety of aromatic substances, and their oily volatile compounds are called essential oils. The main components are alcohols, esters, ketones, hydrocarbons and so on. Some aromatic substances exist in the state of sugar or amino acids and need to be decomposed into essential oils (such as garlic oil) under the action of enzymes. Aromatic substances give food fragrance, stimulate appetite, and are beneficial to human digestion and absorption.

Vegetables contain a variety of pigments, such as carotene, chlorophyll, anthocyanin, lycopene and so on. It makes vegetables colorful, regulates people's appetite to a certain extent, increases the color of food, and is also used as a side dish in cooking.

In addition, some vegetables also contain enzymes, bactericidal substances and some substances with special functions. For example, radish contains amylase, and raw radish can help digestion; Garlic contains phytoncide and sulfur-containing essential oil. Eating garlic raw can prevent intestinal infectious diseases and stimulate appetite. Garlic and onions can lower cholesterol; Bitter gourd has the function of lowering blood sugar, which is related to containing a polypeptide or special protein.