The types of oil present on the market are many and each of them has different nutritional and organoleptic properties. Many types of oil that are excellent raw, however, are not suitable for frying.
The temperatures reached with this cooking method are, in fact, so high that alter the molecular structure of fats, producing residues that are toxic.
Oil for frying, how toxic residues are formed
The formation of toxic residues during frying depends on several factors, mainly:
- Smoke point of oil, i.e. the maximum temperature that an oil can reach before it begins to lose stability and emit harmful substances. The smoke point of an oil it can vary considerably based on the degree of refining, conservation, variety of seeds, cultivation techniques and seasonal trends. The more refined an oil is, the higher its smoke point. A badly stored oil loses its organoleptic characteristics and has a lower smoke point than it would have with an intact molecular structure; the oil, therefore, it must always be stored away from sources of light and heat.
- Temperature and time of exposure to heat. The temperature must not exceed 180 ° C. L'oil used for frying should not be reused several times and you must not add fresh oil to the used one; in fact, the fresh oil is more easily altered in contact with the one already used.
The best oils for frying
Olive oil, especially extra virgin olive oil, is excellent raw and for all types of cooking, including frying. Lately an urban legend has spread according to which olive oil is heavy, in the sense of difficult to digest: that's not true. Olive oil is not poorly digestible either raw or when used for frying; it contains, in fact, excellent quantities of oleic acid, a substance that stimulates the contraction of the gallbladder, aiding digestion.
Olive oil is suitable for frying, thanks above all to the high smoke point, which is on average around 210 ° C, and if the dish is heavy, the responsibility is certainly not for the oil! According to a study published in October 2014 in the Journal of Agricultural and Food Chemistry, olive oil remains the best for frying.
Here are the tips on consuming olive oil
Peanut oil has a smoke point, on average, of around 180 ° C and it can then be used for frying. Some prefer it to olive oil especially for the more neutral flavor. Not everyone, in fact, likes the intense flavor that olive oil gives to fried food and this is one of the reasons why, often, other types of oil are used for frying. Furthermore, peanut oil gives an excellent crunchiness to foods.
Common sunflower oil is not suitable for frying because it has a smoke point too low; usually 130 ° C. Currently, however, sunflower oil exists on the market high oleic, which is extracted from sunflower plants with a particularly high oleic acid content; this oil can be used for frying because it has a smoke point that exceeds 200 ° C.
Other oils found in our kitchens
Other oils that can commonly be found in our kitchens are corn oil e soybean oil. Neither is advisable for frying as they have quite low smoke points.
NB: even if you use the right oil, frying is not a healthy cooking method and should therefore be used in moderation.
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