Cooking food is no easy task. Proper and scientific cooking methods can better retain the anti-cancer components in food. Learning these 5 major cooking skills can help prevent cancer.
1. Wash before cutting to retain vitamin C
Vitamin C, also known as ascorbic acid, is widely found in fresh fruits and vegetables and is effective in preventing and treating esophageal and stomach cancer. To reduce the loss of vitamin C during cooking, you should wash before cutting, cut and then stir-fry immediately, and eat right after cooking. This is because vitamin C is easily soluble in water and prone to oxidation. Do not squeeze out the vegetable juice, as it is rich in vitamin C, enzymes, and other nutrients. Vitamin C is less likely to decompose in an acidic environment, so you can add a little vinegar appropriately. Some people like to add alkali when cooking beans and vegetables to make them soft, but this will destroy vitamin C and reduce the nutritional value of the vegetables. It's best not to do so.
2. Stir-fry over high heat to retain chlorophyll
Chlorophyll in green leafy vegetables is a good chemical protective substance that can hinder the absorption of carcinogens, reduce their effects, and lower the risk of precancerious lesions in various tissues. To retain chlorophyll, one method is blanching, which is to scald the vegetables in boiling water for a few seconds to inactivate the enzymes inside, thereby protecting the chlorophyll from decomposition. Another method is to cook quickly over high heat, using strong fire to cook the dishes quickly, so that the chlorophyll will not be lost too much.
3. Steam or stir-fry cruciferous vegetables
Cruciferous vegetables mainly include cabbage, cauliflower, cabbage, broccoli, kale, etc. This type of vegetable contains plant chemicals such as aromatic isothiocyanates, which are anti-cancer components in the form of glycosides. To maximize the anti-cancer effect of cruciferous vegetables, do not soak them for too long when washing to avoid cell damage. Cut and cook immediately after cutting. If eaten raw, be sure to chew thoroughly to fully release the anti-cancer substances. Steaming and stir-frying have high heat transfer efficiency and do not lose active substances into the water, so they can preserve anti-cancer substances better than boiling.
4. Fish should be steamed or grilled
Fish itself is the best source of protein among meats. Some marine fish are not only delicious and nutritious but also have anti-cancer effects. Fish is rich in B vitamins, such as vitamin B1, B2, B6, and also contains small amounts of vitamin A and vitamin E. To retain nutrients, the best ways to cook fish are grilling and steaming, and the worst is deep-frying. Grilling fish causes little loss of vitamin B2, B6, vitamin A, and vitamin E, with only a slight loss of vitamin B1. At the same time, after grilling, the calcium, potassium, and magnesium content in fish increases significantly. Steaming fish will lose more vitamin A and vitamin B1, but other vitamins and minerals are well preserved. Boiling fish leads to a large loss of water-soluble vitamins, with significant reductions in vitamin B1, B2, and B6, and also mineral loss. Braised fish undergoes complex operations such as pan-frying and pouring oil, resulting in greater loss of vitamins and minerals and an increase in fat content. Deep-fried fish requires high-temperature oil, which causes a large loss of various vitamins and minerals and a significant increase in fat content. In addition, when cooking fish, be careful not to burn it, and do not eat the burnt parts.
5. Key points for cooking with edible oil
Experimental results show that cooking with edible oil alone (i.e., dry-frying) produces a higher concentration of fume than cooking with food added. The "Emission Standard for Cooking Fume in the Catering Industry" stipulates that the maximum allowable emission concentration is 2.0 mg/m³. All cooking methods except boiling exceed the maximum allowable emission concentration. The highest is pan-frying fish, with an average concentration of 25.5 mg/m³, reaching 12.8 times the limit; followed by dry-frying, with an average concentration of 22.0 mg/m³, reaching 11 times; while the fume concentration for fried ribs, fried fish, and fried vegetables is lower, with an average concentration of 2.3~3 mg/m³. Boiling vegetables produces the least fume, at 1.8 mg/m³. The order of fume production from different cooking methods is: pan-frying fish > dry-frying > stir-frying > fried fish and fried ribs > fried vegetables > boiling.
The reason is that for general home cooking, the oil temperature for stir-frying is basically around 240°C, for pan-frying it is basically controlled at 120°C~150°C, for deep-frying it is basically 200°C~230°C, and for dry-frying it can reach 270°C or higher. The higher the cooking temperature, the smaller the diameter of the fume components and the more respirable dust, which is more harmful. Therefore, the fume concentration from dry-frying with edible oil is higher than from cooking with food added, and the fume concentration from stir-frying is greater than from deep-fried foods. The high fume concentration from pan-frying fish may be related to the local burning of the fish during the process.