Oxygen in the air let the oil change quickly, especially as soybean oil, sunflower oil, a relatively high degree of unsaturated edible oil, more easily oxidized once exposed will have a “restless factor” – free radicals, it series of reactions will occur, so that further oil oxidation. Once this process occurs, it got out of hand, its index oxidation process is peroxide value. Initial segment of oil oxidation is quiet, colorless and tasteless. After intermediate oxidation and decomposition, will see a slight sniff “does not taste fresh.” Continued reaches a certain level, it becomes aldehydes, ketones, acids and other substances with a clear “rancid taste” of small molecules. This is called oil “rancid.” The higher the degree of rancidity, peroxide value level will be higher.
Rich in nutrients vitamin E, phospholipids, and carotene. In addition, potassium, phosphorus, iron, magnesium and other inorganic substances it contains for promoting adolescent bones and teeth healthy growth also has some help. Sunflower oil is the public more familiar with a class of oil. It is recommended teenagers can eat this oil daily. Northwestern University study also found that sunflower oil contains α-tocopherol (another form of vitamin E), may be beneficial to human lung function.
Quality sunflower oil is clear and transparent, pale color, not greasy, taste good. And cooked in high temperature, oil temperature does not exceed 180 ℃, the homemade practice of fried, fried, fried cooking methods are appropriate.
Sunflower oil contains large amounts of vitamin E and antioxidant chlorogenic acid and other ingredients, antioxidant capacity is higher. Refined sunflower oil for fried stew temperature is not high, but not solely for frying foods.
It lowers cholesterol more effective than soybean oil, sunflower oil, high linoleic acid, also have some health value. Corn oil can be used for cooking, it is also suitable for use in cold dishes.
Sesame oil is the only vegetable oil without refining, it loses aroma after heated to high temperatures, and thus suitable for cold dishes, or dishes after cooking is completed to get aroma.
Good thermal stability of butter, also has good plasticity, aroma, is an ideal high temperature cooking grease. Vitamin E content is relatively small, but it contains a lot of vitamin A and vitamin D.