The refining degree of first and second grade oils is higher, after degumming, deacidification, decolorization, deodorization and other processes, it has the characteristics of tasteless, light color, high smoke point, less soot from frying, and is not easy to solidify at low temperatures, etc. After refining, the content of harmful components in peanut oil is lower. After refining, the content of harmful components of primary and secondary oils is lower, such as mustard glucoside in vegetable oil can be removed, but at the same time, a lot of nutrients are lost, such as carotene in soybean oil in the process of decolorization will be lost.

Tertiary and quaternary oils are less refined, and only go through procedures such as simple degumming and deacidification. Its color is darker, the smoke point is lower, in the cooking process of the oil smoke, soybean oil and even a larger soybean smell. The degree of refining is low, and the content of impurities in third and fourth grade cooking oils is higher, but at the same time, some carotene, chlorophyll, vitamin E and so on have been retained.

Whether it's first-grade oil or fourth-grade oil, as long as it meets national health standards, it won't cause any harm to human health, and consumers can choose it with confidence. First and second grade oil has higher purity and less impurities, and can be used for cooking at higher temperatures, but it is not suitable for prolonged frying; third and fourth grade oil is not suitable for high-temperature heating, but it can be used for making soups and stews, or used for stuffing and so on. Choose according to your cooking needs and preferences.