Clipart Korea
[[B1]] Olive oil is prized as a health food for its cardiovascular benefits and antioxidant effects, but storing or cooking it the wrong way can strip away much of that value.
[[B2]] Olive oil consumed in South Korea loses quality and effectiveness when its antioxidant compounds, such as polyphenols, break down after exposure to light, heat and oxygen during storage, or when it is heated past its smoke point, the food industry said on the 18th.
[[B3]] Light, heat and oxygen are the three main causes of rancidity in olive oil. Exposure to these conditions dulls the flavor and reduces the level of polyphenols, an antioxidant. The industry advises keeping bottles in a cool, dark place and, for clear containers, wrapping them in foil or dark-colored film to block light. Closing the cap immediately after use to limit contact with air is also seen as essential. Refrigeration, by contrast, is not recommended, because low temperatures can cause the oil to cloud and solidify or to form sediment, hurting both quality and usability. Temperatures above 30 degrees Celsius also speed up oxidation.
[[B4]] The choice of cooking method matters too. Virgin oils, pressed directly from olives, and especially extra virgin, have a low smoke point of around 170 degrees Celsius, making them unsuitable for high-heat cooking. Heating them beyond that point destroys beneficial compounds such as squalene and tocopherol, and in severe cases can even produce harmful substances such as trans fats or benzopyrene, so they are best suited to uncooked dishes such as salads, seasoned vegetables and dressings. Pure olive oil, which blends virgin oil with refined oil, has a higher smoke point of 180 to 240 degrees Celsius and can be used widely for high-heat cooking such as stir-frying and deep-frying.
[[B5]] Rancidity is not unique to olive oil. Cooking oils sold in stores generally have a shelf life of about two years at room temperature, and olive oil is similar at around two years. After opening, however, oxidation accelerates under the influence of air, light and temperature, so use within three to six months is recommended. A Korea Consumer Agency survey also found cases in which cooking oil that had been open for more than six months showed rancidity levels exceeding the standard. Sesame oil, too, has a shelf life ranging from six months to two years depending on the type, but it shares the same tendency to spoil easily when exposed to air and sunlight. Regardless of the type of oil, storing it away from light, heat and oxygen, and choosing a cooking method matched to its smoke point, are the common conditions for preserving its health benefits.