Nutrition: The nutrients of vegetables mainly include minerals, vitamins and fiber. The higher the content of these substances, the higher the nutritional value of vegetables. In addition, the content of water and dietary fiber in vegetables is also an important nutritional quality index. Generally, vegetables with high water content and less dietary fiber have better freshness and higher edible value. But from the perspective of health care, dietary fiber is also an essential nutrient. The nutritional content of vegetables should not be underestimated. According to FAO's statistics in 1990, 90% of vitamin C and 60% of vitamin A necessary for human body come from vegetables, which shows the great contribution of vegetables to human health. In addition, there are many phytochemicals in vegetables that are recognized as beneficial to human health, such as carotenoids, dipropylene compounds, methyl sulfur compounds and so on. Many vegetables also contain unique trace elements, which have special health care effects on human body, such as lycopene in tomatoes and prostaglandin in onions.
Classification: Although there are about 20 families of vegetables widely cultivated in China, some common species or varieties are mainly concentrated in 8 families.
(1) Cruciferae: including radish, turnip, Chinese cabbage (including Chinese cabbage and Chinese cabbage subspecies), cabbage (including varieties of cabbage, kohlrabi, cauliflower and broccoli), mustard (including varieties of mustard and potherb mustard), etc.
(2) Umbelliferae: including celery, carrot, fennel, coriander, etc.
(3) Solanaceae: including tomato, eggplant and pepper (including sweet pepper varieties).
(4) Cucurbitaceae: including cucumber, zucchini, pumpkin, bamboo shoots, wax gourd, loofah, gourd, bitter gourd, bergamot, etc.
(5) Leguminosae: including kidney beans (including varieties of dwarf kidney beans and trailing kidney beans), cowpeas, peas, broad beans, edamame (i.e. soybeans), lentils and canapes.
(6) Liliaceae: including leek, scallion, onion, garlic, leek, day lily, asparagus, lily, etc.
(7) Compositae: including lettuce (including lettuce and lettuce varieties), lettuce, chrysanthemum, burdock, Jerusalem artichoke, etc.
(8) Chenopodiaceae: including spinach and beet (root beet and leaf beet varieties).
Vegetables are not only healthy food with low sugar, low salt and low fat, but also can effectively reduce the harm of environmental pollution to human body, and at the same time, vegetables can also prevent various diseases.