Can air fryers produce carcinogens? How to use them healthily

In recent years, many families have bought air fryers, thinking that the food they cook is oil-saving and crispy . However, some people have heard that air fryers are not healthy and can produce carcinogens!

Can the air fryer still be used? This article will give you a careful review.

First of all, what is the difference between an air fryer and deep frying or an oven?

The principle of deep frying is that after food enters the hot oil, the water in it quickly reaches the boiling point and evaporates quickly, dehydrating the food. The gaps left by the evaporation of water molecules make the food loose and crispy. However, grease will also enter the gaps, which will greatly increase the fat content of the food. If the oil containing more saturated fat is used, it is semi-solid at room temperature, and it will not feel greasy after entering the food, and it will provide a crispier taste.

The principle of baking food in an oven is to surround the food with hot air, so that the surface gradually dries and forms a dense, crisp and hard shell. Because the oven is heated in a static state, the heat enters the food slowly, and the moisture inside is protected by the hard shell, so that the food can remain soft for a longer time.

The cooking principle of an air fryer is to allow heated air to circulate rapidly in a closed pot, replacing hot oil with hot air, causing the temperature of the food to rise rapidly, especially allowing the moisture on the surface of the food to evaporate quickly [1].

That is to say, compared with an oven of the same power, an air fryer can make the surface of food lose moisture at a faster rate, forming a crispy shell, while the middle part remains soft while reaching the cooking temperature. In this way, the cooking effect of frying and roasting is quickly achieved - "crispy on the outside and tender on the inside". And this effect is achieved without adding oil, or with only a small amount of oil .

For foods that have very little fat content, such as steamed buns, bread, etc., the function of the air fryer is to dry-bake them quickly .

For foods that are high in fat, such as spareribs and chicken wings, the air fryer not only performs the dry-roasting function, but also quickly heats the fat in the meat, creating a frying effect inside the ingredients .

Secondly, frying will produce harmful substances such as benzopyrene, heterocyclic amines and acrylamide. Will the air fryer also have this problem?

Yes, air fryers can also cause similar problems. This is because the production of harmful substances is related to temperature . No matter what method is used to cook, high temperature is needed to achieve crispy and dry results.

The operating temperature of an air fryer is usually between 150 and 200 degrees Celsius, and the deep-frying temperature is between 160 and 180 degrees Celsius. Acrylamide will be produced if the temperature exceeds 120 degrees Celsius. The production of acrylamide is usually related to the degree of browning of carbohydrate foods. Therefore, since air fryers can make food turn yellow and crispy just like deep-frying, it is difficult to avoid the problem of acrylamide production [2].

At the end of 2019, the Korea Consumer Agency released a test report on 10 air fryers and found that when frozen French fries were air-fried at above 200 degrees Celsius as recommended in the instructions, the acrylamide content in French fries produced by four products exceeded EU standards.

If you are heating foods such as chicken wings and spareribs that contain fat and protein, then whether you use an air fryer or deep-fry, as long as the actual temperature of the protein and fat reaches above 200 degrees, carcinogens such as heterocyclic amines and polycyclic aromatic hydrocarbons (such as benzopyrene) will also be produced.

However, compared to deep frying, the production of harmful substances in air frying is significantly reduced. This is because the air fryer is heated only once. When frying, the oil is usually not used for only a few minutes, and the harmful substances produced by repeated heating of the oil will accumulate over time. When frying, the frying oil that has been overheated and has oxidative polymerization problems will enter the food, but air frying will not have this problem.

The lipid oxidation products themselves will react with the protein decomposition products to form a large amount of acrylamide and advanced glycation end products (AGEs) . Excessive AGEs, like acrylamide, are components that promote inflammatory responses and also promote aging and chronic diseases. Therefore, reducing the use of frying oil itself will help reduce the pro-inflammatory nature of food .

On the other hand, air fryers can more conveniently adjust the heating temperature and time. By controlling the temperature and duration, reducing the degree of food browning and reducing the requirements for a crispy taste, the production of harmful substances such as acrylamide, heterocyclic amines and polycyclic aromatic hydrocarbons can be reduced.

Third, frying produces oil smoke. Will the air fryer also cause oil fume pollution?

Everyone knows that frying produces fumes, which contain a large amount of harmful substances. Inhaling fumes will increase the risk of lung cancer.

If it is used to fry fatty foods at a high temperature, cooking with an air fryer will also produce fumes, which will pollute the kitchen environment. Even if you use an electric baking pan or electric oven, this problem is unavoidable.

For example, when grilling chicken wings, the subcutaneous fat cells of the chicken wings will release fat due to the heat, and the fat will produce smoke under the high temperature of nearly 200 degrees Celsius.

Therefore, when cooking fatty foods in an air fryer, it is best to place it near a range hood or open the kitchen window and exhaust fan.

Of course, compared with deep frying, the air fryer produces less oil smoke. On the one hand, it does not require as much oil, the total amount of fat heated is relatively small, and the oil smoke production is relatively small. On the other hand, it can reduce the oil smoke production by lowering the set temperature, while it is more difficult to control the heat when deep frying.

Total volatile organic compounds (TVOC) are a general term for various organic compounds that can evaporate into gas at room temperature. They are toxic, irritating and carcinogenic, and have acute damage to human health. Some scholars have measured the TVOC concentrations produced by seven types of kitchen heating appliances in working conditions, including air fryers, electric ovens, multi-function grills, electric kettles, electric rice cookers, electric baking pans, and disinfection cabinets.

The results showed that the TVOC concentration released by the seven electric kitchen appliances was the highest in the first working cycle after they were put into use. The emissions from air fryers and electric ovens were similar, both slightly exceeding the national standard limit (less than 0.8 mg per cubic meter). This may be because the anti-rust coating and non-stick coating in them are released after being heated [3]. However, it is reassuring that by the 10th working cycle, the emissions from the air fryer had dropped significantly to less than one-tenth of the initial use, which is even lower than that of the rice cooker.

Fourth, compared with cooking in an oven or deep frying, will the loss of nutrients in an air fryer be greater?

What consumers value more is that when using air frying, the amount of oil used in the cooking process can be greatly reduced, and the oil content in many foods will not increase at all. For example, when using it to bake steamed bread slices and sweet potatoes, there is no need to add oil. There is no need to add oil when baking saury or chicken wings. This will not significantly increase the caloric value of the food, and it can even reduce the fat content because of the oil released during baking.

In addition to avoiding the increase in caloric value, the loss of fat-soluble nutrients in air fryers is usually relatively small when the heating temperature is the same. This is because air fryers do not require a large amount of oil for frying, which effectively reduces the loss of fat-soluble vitamins and health-promoting ingredients in food. For example, vitamin A, vitamin E, vitamin K, carotene, lutein, etc. can all be better preserved. Other studies have shown that compared with deep-frying, air-fried French fries can not only reduce the fat content by 70%, but also reduce the loss of vitamin C[4].

Studies have also found that the fat content of air-fried chicken nuggets can be reduced by 25%, and the oxidative decomposition of fatty acids is also significantly reduced[5].

Some researchers have studied the cooking effects of air fryers, hot air drying, and traditional deep-fried shrimp. The results show that air fryers have the best sensory evaluation when heated at 150°C for 6 minutes, which is better than other cooking methods. Air-fried shrimp tastes sweeter than hot air drying, has a higher digestibility than deep-fried shrimp, and has a lower degree of oxidation than hot air drying shrimp. In short, from the perspective of cooking shrimp, air frying has comprehensive advantages [6].

At the same time, because no or little oil is added, the proportion of omega-3 fatty acids in aquatic ingredients such as fish, shrimp and shellfish changes little, and they will not absorb a large amount of saturated fatty acids during the frying process like fried fish.

However, air frying will always result in some loss of nutrients[7]. Due to the rapid rotation of hot air, the ingredients on the surface of the food will be oxidized more quickly. For example, omega-3 fatty acids, polyphenols, and vitamin E will be lost. If highly unsaturated oils are brushed on or mixed into the surface of the food during frying, the polyunsaturated fatty acids in them will oxidize quickly. Ingredients such as DHA and EPA in fish will also be lost.

Therefore, when making air-fried French fries, it is not suitable to use linseed oil, walnut oil, soybean oil and other oils with particularly high unsaturation. Just like fried foods, palm oil, coconut oil, lard, butter, etc. are more suitable.

In fact, it is meaningless to compare the nutritional losses of oven, deep frying and air fryer without considering the specific cooking effects, because the taste effect, harmful substance production and nutrient loss effects are inconsistent when cooking at different times and temperatures.

When frying, if the frying time is too long and the oil temperature is too high, it will increase the formation of harmful substances and the loss of nutrients.

If the oil temperature is too low, although the production of harmful substances will be reduced, it will lead to excessive oil absorption and a significant increase in fat content.

When cooking with an air fryer, if the frying plan is unreasonable, the temperature is too high, or the time is too long, the texture will deteriorate, the nutrient loss will increase, and acrylamide and lipid oxidation products will increase. For example, if the total amount of grilled chicken nuggets is less, the color is darker, the taste is crisper, more sugar and starch are added, and the chicken nuggets contain more fat, then the total amount of acrylamide produced after air frying will be greater.

Summary: The air fryer can be used.

It reduces the amount of cooking oil used and helps reduce the caloric value of food.

It reduces the oil-soluble loss of fat-soluble nutrients and also lowers the yield of oil oxidation polymerization products.

However, after all, it is high-temperature heating, it will still produce acrylamide and still cause oxidative loss of vitamins and polyunsaturated fatty acids.

If it is used to cook oily foods, it will still produce fumes. Pay attention to kitchen ventilation and it is best to operate next to the range hood. Especially when it is used for the first time, turn on the range hood and open the windows to reduce the harm of volatile organic compounds.

For ordinary consumers, they should also accumulate experience in cooking and explore how to optimize the cooking temperature and time. It is better to have a lighter color and a shorter cooking time than to overcook.

References:

1 Zaghi AN, Barbalho SM, Guiguer EL, et al. Frying process: from conventional to air frying technology. Food Revews International, 2019, 35(8):763-777

2 Sansano M, Juan-Borras M, Escriche I, et al. Effects of pretreaments and air-frying, a novel technology, on acrylamide generation in fried potatoes. Journal of Food Science, 2015, 80(5):1120-1128

3 Wu Xiangbin, Yu Xiao, Hu Fen, et al. Detection of TVOC emission from electric kitchen appliances. Daily Electrical Appliances. 2019(05):29-31

4 Teruel MR, Gordon M, Linares MB, et al. A comparative study of the characteristics of French fries produced by deep fat frying and air frying. Journal of Food Science, 2015, 80(2):349-358

5 Cao Y, Wu, G, Zhang F, et al. A comparative study of physicochemical and flavor characteristics of chicken nuggets during air frying and dieep frying. Journal of the American Oil Chemists' Society, 2020, 97(8):901-913

6 Zhou Gaohui. Effects of air frying on the quality and in vitro digestibility of Penaeus vannamei[D]. Guangdong Ocean University, 2022

7 Wang Jun, Wang Ying, Chen Zhe, et al. Research progress on the application of air frying technology in food processing. Gastronomy Research, 2021, 38(02), 49-53