The microwave oven has become an essential kitchen appliance in every household. Besides heating food, people also use it to steam eggs, stir-fry dishes, and even cook soups. It's convenient and eliminates the hassle of smoke and fumes, making it particularly popular with housewives. But how does microwave cooking compare to traditional methods like pan-frying, boiling, and stewing? Is it better or worse?
Microwave cooking is a new method that heats food molecules quickly. It primarily heats the water molecules in food, making it suitable for various moisture-rich foods.
Microwave cooking can better preserve vitamins. Because it is more efficient, requires less time, and releases less water, the loss of various vitamins when food is cooked to completion or sterilized is lower than with pan-frying and significantly lower than with boiling.
Microwave cooking can keep vegetables fresh. A study using green asparagus illustrates this point. To make canned asparagus, researchers designed several sterilization systems: a microwave circulating water heating system, a high-pressure water heating system, and a conventional steam heating system. The final results showed that the antioxidant activity of the microwave-sterilized asparagus was higher than that of the other two methods. Microwave cooking helps maintain the fresh green color of vegetables with less loss of chlorophyll. For example, after microwave cooking, bitter vegetables lost only 8.2% of their chlorophyll, while after blanching, the loss was as high as 46.9%.
Microwave ovens can also reduce carcinogens produced during heating. Research has found that microwave heating is short and easy to control, which prevents uneven or excessive heating. This reduces carcinogens formed from high-temperature cooking, such as heterocyclic amines from overheated proteins and acrylamide from overheated starchy foods.
However, every advantage has its disadvantage. Microwave cooking might reduce the content of beneficial fatty acids in meat. In a recent study, the changes in fatty acids in beef after heating were measured. Some samples were heated by microwave, and others by conventional steaming, until the internal temperature was the same. The results showed that compared to steaming, microwave heating significantly decreased the proportion of omega-3. In contrast, lower-temperature steaming has a smaller impact on unsaturated fatty acids and can even slightly increase the content of polyunsaturated fatty acids.
Therefore, microwave cooking is more suitable for high-moisture, low-fat foods like soups and vegetables. For foods rich in omega-3, such as fish, duck, seafood, and egg yolks, it is better to choose traditional steaming methods.