Blanching is a common cooking process, but do you really know how to blanch? Blanching water is very healthy if done right, but if done wrong, it will greatly reduce the nutrition and taste. Before cooking these types of dishes, make sure to blanch them first. Vegetables with high levels of oxalic acid have oxalic acid, which is an anti nutritional component found in many vegetables, but there are differences in its content. Excessive intake of oxalic acid in daily diet can form insoluble substances with calcium before absorption, hindering calcium absorption. After absorption, it can also form insoluble oxalates with calcium and other substances in the body, increasing the risk of developing stones. Spinach, water spinach, celery, amaranth, purslane and other vegetables have relatively high oxalic acid content, and require certain pre-treatment to remove oxalic acid before consumption. Oxalic acid is easily soluble in water, and most of it can be removed by blanching in hot water. A study has shown that when 180 grams of spinach are placed in 1000 milliliters of boiling water and blanched for 1 minute, 2 minutes, 3 minutes, and 4 minutes, the removal rates of soluble oxalic acid are 43%, 50%, 54.7%, and 58.9%, respectively. The removal rate of oxalic acid in spinach by oil frying is not high, not exceeding 5%, and even increasing the amount of cooking oil has little effect. In addition, the oxalic acid content of purslane is as high as 1460mg/100g. Although the oxalic acid removal rate can reach over 50% after boiling for 3 minutes, it is still higher than most vegetables. It is better to eat less. 02 Vegetables with inherent "toxins" Some vegetables have inherent "toxins", and not blanching or eating them raw may lead to food poisoning, which can be fatal in severe cases. Beans and green beans contain saponins (g ā n), which contain hemolysin that can damage red blood cells. Saponins have a strong stimulating effect on the gastrointestinal mucosa, causing congestion, swelling, and hemorrhagic inflammation, and can cause symptoms such as nausea, vomiting, abdominal pain, and diarrhea. This ingredient is relatively sensitive to heat. Heating at 100 ℃ for more than 10 minutes, or stir frying at higher temperatures, can break down saponins and eliminate the toxicity of harmful substances. Blanching before cooking is a good way to avoid poisoning. Eating a certain ingredient in fresh yellow flowers can cause nausea, vomiting, dry mouth and tongue, and diarrhea. As for what exactly this ingredient is, it is currently unclear. In the past, people believed it was colchicine, but there are also views that day lily does not contain colchicine, but rather a co efflux component of multiple compounds, which is easily soluble in water and can be decomposed by steam or blanching. Boiling water for 3-5 minutes can be safely consumed. When vegetables with high nitrite levels mention "nitrite", many people think of it as "carcinogenic". In fact, nitrite itself is not carcinogenic, but when it is consumed by our body, it will generate nitrosamines in the environment of stomach acid. Nitrosamines are carcinogens, and excessive intake can increase health risks. Vegetables with high nitrite content must be blanched before cooking. The nitrite content in Chinese toon is higher than that of ordinary vegetables, so don't eat dipping sauce with Chinese toon again. Even if it's fried eggs, they need to be blanched first. Vegetables and aquatic plants that may be contaminated by parasites, such as water chestnuts, lotus roots, and water chestnuts that we often eat. Direct consumption may lead to infection with ginger worms, which can cause mild abdominal pain, diarrhea, nausea, and fever. In severe cases, it can also cause intestinal obstruction and even death. Blanching before cold mixing can ensure food safety. Some vegetables that are difficult to clean have uneven surfaces, such as broccoli and cauliflower, which not only easily accumulate dirt and grime, but also have pesticide residues. However, broccoli is relatively rich in vitamin C in vegetables. Do not blanch for too long to avoid losing all the vitamin C. Generally, blanching for 1-2 minutes is sufficient. What must be known before blanching? Blanching may seem simple, like "boiling water+ingredients", but there are still many precautions to be taken in actual operation. Do these 4 things well to make your blanched food healthy and delicious! Is blanching done with hot water or cold water? Generally speaking, most vegetables are suitable for boiling water to maintain their nutrition and taste to the greatest extent possible. For larger ingredients such as potatoes and carrots, cold water can be chosen to cook them thoroughly. How much water should be added for blanching? It is best to use the ingredients all at once, and try to avoid repeatedly adding water, which can cause excessive blanching time and loss of nutrients. How long does it take to blanch? Most leafy vegetables only need to be blanched for 1 minute. It is recommended to blanch the vegetables first and then cut them. After blanching, immediately put them in cold water to cool down and drain them. Do not squeeze excessively to avoid nutrient loss. Blanch broccoli, cauliflower, and fungus in water for 1-2 minutes; Water chestnuts, lotus roots, etc. should be blanched in boiling water for at least 1 minute; It is recommended to blanch beans and green beans for at least 10 minutes; It is recommended to blanch fresh yellow cabbage in water for 3-5 minutes. Vegetables like bamboo shoots and bamboo shoots can be cooked for a while longer. Do not reuse the water that has been blanched to dissolve oxalic acid in water. The longer the blanching time, the higher the oxalic acid content in the soup. It is not recommended to drink or use it again for cooking. (New Society)