To better absorb vitamins from vegetables, it is essential to protect them. In our daily washing, cutting, and cooking processes, some incorrect methods can lead to significant loss of vitamins in vegetables. Therefore, every step of cooking should not be overlooked; we must protect the nutritional value of vegetables while also removing any pesticide residues.
Washing Vegetables—Wash Before Cutting
When washing vegetables, you should wash them before cutting, because many vitamins are water-soluble. Once vegetables are chopped, their surface area in direct contact with water increases many times over, causing water-soluble vitamins (such as B-complex vitamins, vitamin C, and water-soluble fiber) to dissolve and be lost in the water. At the same time, chopped vegetables have a greater chance of surface contamination by bacteria, creating a health hazard. Therefore, vegetables should be washed before being cut.
To remove pesticide residues, the method of washing also matters. Experiments have shown that soaking vegetables in tap water for 10-60 minutes before gently scrubbing can remove 15%-60% of pesticide residues. For some heat-tolerant vegetables, such as cauliflower, beans, green peppers, and celery, blanching them in boiling water for a few minutes after washing can reduce pesticide residues by about 30%, and subsequent high-temperature stir-frying can essentially eliminate the pesticides on the vegetables. Cutting Vegetables—Larger Pieces are Better Than Smaller
After fresh vegetables are washed and cut, their contact with oxygen in the air increases. Therefore, cutting vegetables into cubes results in less nutrient loss than shredding or slicing them. For some vegetables with peels, like radishes, the peel contains more vitamins than the flesh. Try not to peel them when eating to avoid unnecessary nutrient loss. Stir-frying—High Heat and Quick Cooking
When cooking, using high heat and cooking quickly is a sound principle. Vitamin C is most easily oxidized at 60°C-80°C. High-heat, quick stir-frying can minimize vitamin loss. The method of blanching vegetables in boiling water before stir-frying seriously depletes vitamins and inorganic salts. When cooking vegetables, the heating time should not be too long, not too much water should be added, and the pot lid should not be covered tightly, which helps to maintain the green color of the vegetables. Stir-fried vegetables should be eaten immediately; otherwise, not only will their color, aroma, and taste change, but their vitamin content will also decrease over time.
Additionally, many people now believe that eating vegetables like cucumbers and tomatoes raw allows for better absorption of vitamins, as the vitamins are not destroyed by processing. However, Bian Huawei, Deputy Director of the Nutrition Department at the Third Affiliated Hospital of Sun Yat-sen University, believes that most nutritionists currently do not recommend eating vegetables raw due to concerns about potential pesticide residues. If you feel that the vitamins in your vegetables are insufficient, you can supplement your intake by eating fruits.