The "Dietary Guidelines for Chinese Residents (2022)" emphasizes that vegetables should be included in the meal, ensuring that the daily intake of fresh vegetables is not less than 300g, with dark vegetables accounting for 1/2 of the total. While vegetables play an important role in maintaining normal physiological activity and improving health through immune regulation, improper storage and processing of vegetables can greatly reduce their nutritional value. Today, let's explore: How to maximize the nutritional value of vegetables? Storage: Short term storage at 0-4 ℃ is preferred. Long term vacuum freezing is recommended for many vegetables, which are harvested before the highest vitamin C content, to achieve the longest shelf life and facilitate storage and transportation. After vegetables arrive at the market, they often stay on the shelf for a few hours to two days, and after that, they may stay in the household refrigerator for another 2-3 days. During this period, the nutrient content may change significantly. Wilting and high temperature promote the loss of vitamin C, so after 24 hours at room temperature, not only the vitamin content of green leafy vegetables significantly decreases, but also the nitrite content increases rapidly. The higher the temperature, the faster the change. When storing vegetables for a short period of time, it is not advisable to store them at room temperature, preferably at 0-4 ℃, and attention should be paid to placing them in bags to prevent moisture evaporation. When vegetables are frozen under - 18 ℃ for 3 months, there is no significant change in nutrient content. Generally speaking, the vacuum freeze drying method has the smallest nutrient loss, and due to the concentration effect, the nutrient content after drying increases. Dried vegetables are susceptible to oxidation, so they should be stored in vacuum packaging and stored at a lower temperature. Option 2: Discarding the outer layer or peeling it too thick can result in loss of nutrients. Choosing vegetables is one of the key elements of nutrient preservation. Discarding the outer layer of leaves or peeling them too thick can cause nutrient loss because the nutritional value of the outer green leaves of vegetables is higher than the yellow and white leaves in the center, and the nutrient concentration of the outer layer of the skin is higher than the center. For example, the concentration of carotene in the outer green leaves of cabbage is more than 20 times higher than the white core, and the mineral and vitamin C are several times higher. Washing: Washing and then cutting, and processing vegetables immediately after cutting is another important process. The correct approach: Wash first and then cut without damaging the leaves. When cutting vegetables, when it is necessary to cook for a long time, you can cut large pieces. If you cut small pieces or shreds, you should cook quickly to reduce the possibility of nutrients oxidation under high temperatures. If you cut vegetables before washing them, try to rinse them with running water instead of soaking them in water for a long time. Soaking after washing will cause a large amount of nutrients to dissolve in water and lose. Washing vegetables after cutting can cause excessive loss of water-soluble vitamins and minerals from the cut. After washing, process and eat as soon as possible. Cooking: Preferably eaten raw, it is recommended to stir fry quickly over high heat. The better ways to avoid long-term cooking of vegetables and vegetables are cold mix, rapid fry over high heat, and rapid steaming. The vitamin C retention rate of fried vegetables is between 45% and 94%. Vegetables with high vitamin C content that can be eaten raw should be served as cold as possible, or blanched in boiling water for one minute before consumption. Green leafy vegetables with a high carotene content can be quickly fried because oil can promote the absorption of carotene. When frying vegetables, the oil temperature should not be too high, and the time should not be too long. It is better to just soften the vegetables to avoid excessive loss of vitamin C. Use hot soup with oil