Introduction: In daily life, improper cooking can easily lead to the loss of food nutrients. The three methods recommended in this article—high-heat stir-frying, steaming, and stir-frying with a lid—can effectively preserve the nutrients in food.
For healthier eating, many families are already controlling oil and salt during cooking. However, many people don't realize that controlling cooking temperature and time is equally important and can reduce nutrient loss in food.
Cooking temperature and time have a significant impact on food nutrients, especially water-soluble vitamins like Vitamin C. Once heated, their loss is unavoidable, and the higher the temperature and the longer the time, the greater the loss. Although eating raw vegetables and fruits like cucumbers and tomatoes allows for more vitamin intake, many foods are difficult to swallow when uncooked. Furthermore, cooking not only improves the texture of food but, more importantly, eliminates the health threat from microbial contamination. By cooking thoroughly while controlling temperature and time as much as possible, you can maximize nutrient retention and avoid the formation of carcinogens caused by excessively high temperatures. Here are three methods to achieve this.
High-heat stir-frying. Many nutrients are easily lost in the 70°C to 85°C temperature range. High-heat stir-frying rapidly increases the temperature in the wok and speeds up the cooking process, reducing the time food is exposed to high heat, thereby minimizing nutrient loss. Dishes cooked this way are delicious and aromatic, with Vitamin C loss of less than 20%. If a little vinegar is added during the process, it is even more beneficial for preserving nutrients that prefer an acidic environment and are sensitive to alkalinity, such as Vitamin C, B1, and B2. It should be noted that too much oil at the bottom of the wok should be avoided, as it can cause the temperature to become too high, which in turn accelerates nutrient loss.
Steaming. Compared to deep-frying and stir-frying, methods like steaming, boiling, stewing, and blanching have relatively lower temperatures in the pot, generally around 100°C, which helps in nutrient retention. However, these methods have their drawbacks. During boiling and stewing, a large amount of nutrients leaches into the water. If the water is not consumed along with the food, significant nutrient loss occurs. Blanching involves a higher initial temperature and shorter heating time, resulting in less nutrient loss than boiling or stewing with cold water. However, it's important to maintain a rolling boil, adding vegetables in small batches to prevent a sharp drop in pot temperature and an extension of blanching time, which would cause nutrient loss. In comparison, steaming over boiling water is the best method. The steam temperature is above 100°C, which shortens the heating time, allowing the vast majority of nutrients in the ingredients to be retained. Additionally, the moisture in the steam helps to maintain the food's texture.
Cooking with a lid. Vegetables with a firmer texture, such as cauliflower, potatoes, eggplant, green beans, and carrots, are often difficult to cook through. It's best to cover the pot and use a braising method to increase the internal temperature and shorten cooking time. Experiments have shown that cooking without a lid can result in 2 to 3 times more loss of Vitamin B2 and a large amount of Vitamin C compared to cooking with a lid.
Many common cooking practices can also significantly reduce nutritional value. For example, vitamins gradually degrade if fruits and vegetables are not eaten promptly after purchase, and repeated washing of rice can cause substantial loss of vitamins and minerals.