In recent years, the number of people with food allergies has increased rapidly, which is thought to be related to factors such as environmental changes and antibiotic use. How are allergic reactions produced, what are the hazards to the human body, and what are the common food allergies? The 20th issue of the "School Media" scientific papers sponsored by the Science Media Center of China Science Research Institute was recently held at the Beijing Academy of Food Science, focusing on "food allergens in life", from medicine, nutrition, food science, etc. Experts in the field shared some research progress on food allergens. According to experts, high temperature, high pressure, microwave and other processing methods can change food sensitization, and appropriate processing methods can help reduce food allergenicity.
Food allergy has become a global health problem
Xue Wentong, a professor at the College of Food Science and Nutritional Engineering of China Agricultural University, said that food allergy has the characteristics of being lifelong and difficult to cure. 20%-30% of the world's population suffers from food allergies, and the incidence rate is increasing year by year.
Ma Tingting, deputy director and deputy director of the Department of Allergy, Beijing Shijitan Hospital, said that food allergies, ie food allergies, refer to the abnormal immune response of the body after the food enters the human body, leading to disorder and/or tissue damage of the body's physiological functions. This in turn triggers a series of clinical symptoms. Common food allergies are milk, eggs, peanuts, soybeans, wheat, nuts, fish, shrimp, crab, shellfish, etc. Allergic diseases are mainly divided into 4 types. Food allergy can be mainly divided into immediate and delayed type hypersensitivity reactions. The former can occur within a few minutes after the intake of allergens, which may cause severe allergic reactions; the latter is usually taken It occurs within hours to days after entering the allergen, and the symptoms are relatively mild. Clinical food allergies are mainly fast-acting, usually manifested as oral allergic syndrome, respiratory symptoms, gastrointestinal symptoms and the like. Allergic diseases are one of the common chronic diseases in the world. They have high prevalence, impaired quality of life, and affect learning and sleep. The complex causes multiple organs. It is a long-term chronic disease that requires long-term control. The key to prevention and treatment of allergic diseases is to identify allergens, and pay attention to symptomatic treatment, desensitization treatment, and avoid contact with allergens during the treatment. Infants and children have poor gastrointestinal barriers, low digestive enzyme activity, low gastric acidity, and immature immune system, so the prevalence of food allergies is higher than that of adults. Patients with a sensitized food allergen should be fasted to the food and all foods containing that food ingredient.
Processing can change food allergenicity
Xue Wentong said that the vast majority of food allergies are caused by protein in food. Fermentation, baking, frying, stirring, cutting and other food processing methods can change the structure of the protein contained in the food itself, or use it in combination with other ingredients. Thereby reducing food allergenicity. For example, Chinese favorite boiled and fried peanuts have lower sensitization than roasted peanuts that Europeans often consume, and fermented taro is less susceptible to allergies than wheat. The results of the Xue Wentong team also showed that gastrointestinal digestion can change the structure of allergens, which in turn affects sensitization. A good gastrointestinal environment can reduce the incidence of food allergies. Therefore, he advises patients with food allergies to maintain gastrointestinal health in addition to being away from allergens.
Che Huilian, executive deputy director of the Special Food Research Center of China Agricultural University, said that food heat treatment can destroy the secondary structure and tertiary structure by changing the interaction of intramolecular or intermolecular covalent or non-covalent bonds, affecting the conformation table. In order to change the sensitization of food protein, different heat treatment methods have different changes in food sensitization. Food heat treatment mainly includes dry heat and wet heat treatment, high temperature and high pressure treatment, microwave treatment and the like. Taking raw walnuts as an example, scientists found that in experiments based on serological evaluation methods, dry heat processing methods such as baking have little effect on the sensitization of walnuts, while hot and humid processing methods such as cooking can significantly reduce walnut sensitization. Sex, the addition of high temperature and high pressure processing method on the basis of damp heat is more obvious; on the contrary, microwave heating will increase the sensitization of walnut.
Che Huilian speculates that this may be due to the fact that the ordinary heating method is to gradually transfer heat to the inside of the food through heat conduction, so that the spatial structure of the substances causing sensitization and the like are gradually opened, and the water will destroy the original structure of the sensitizing substance. The sensitization is reduced; while the microwave heating is uniformly heated from the inside of the food, the sensitized structure is exposed but not damaged, and the protein solubility is enhanced to cause the sensitization to rise. According to reports, a similar situation has been found in the sensitization study of peanuts. In addition, many studies have confirmed that the treatment of food allergy can be desensitization therapy, drug therapy, etc., in addition to the appropriate amount of vitamin C supplement, and pay attention to rest.
Yan Ping, an associate researcher at the State Key Laboratory of Food Science and Technology at Nanchang University, said that as a high-nutrition food, eggs are a good source of high-quality protein for people of all ages above 6 months of age. However, there are four kinds of allergens in egg from egg yolk and egg white. Among them, four allergens such as egg mucin, egg albumin, egg transferrin and lysozyme from egg white may cause allergic reaction after eating.
The research team found that the heat treatment can reduce the sensitization of the egg, and the sensitization gradually decreases with increasing temperature and time within a certain range. Take the actual processing as an example, the possibility of allergies caused by different ways of eggs: raw eggs> æº heart eggs> boiled eggs> stewed eggs. In addition, the egg is dried to form egg powder and then added to the food can also effectively reduce its sensitization. In this regard, she suggested that if the individual is determined to be allergic to the egg, then choosing an egg that is "older" will be safer than eating the egg, or by choosing a baked food containing eggs, such as cake, bread, or during cooking. Use egg powder instead of eggs to minimize the incidence of allergies.
Pay attention to rare food allergies
Che Huilian reminded that allergies caused by walnuts belong to immunoglobulin E (IgE)-mediated rapid allergic reaction. Although the incidence is low, it is often accompanied by serious clinical symptoms, and even causes shock, death, etc., which has attracted much attention from the industry. . In addition, walnuts have similar structural and spatial conformations to some of the proteins in almonds, cherries, plums, etc., which means that people who are allergic to walnuts may also be allergic to almonds, cherries, and plums, and vice versa, to almonds, cherries, and plums. People who are allergic may also be allergic to walnuts. Because the allergies caused by walnuts are not common, they are often overlooked. It is recommended that Che Linlian increase the corresponding testing items in the future to avoid serious allergies.
According to Wu Ping, because the allergic symptoms caused by eggs are very similar to ordinary allergies, it is rarely heard in daily life. But in fact, in China, the highest incidence of egg and milk allergy, is also the top allergen food in infants and children. Egg allergy symptoms are gastrointestinal, skin, respiratory discomfort, long-term egg allergy may induce asthma, eosinophilic esophagitis, etc., in some serious cases can even cause asphyxia, life-threatening. With the advancement of science and technology, the treatment of egg allergy in the past has been strictly avoided. Now, the method of avoiding + inducing tolerance is adopted. Eggs processed by sufficient heating or other methods are being studied to establish egg immune tolerance. In addition, studies have shown that because the incidence of egg allergy will decrease with age, the appropriate supplement of vitamin D for infants aged 0-2 can reduce the incidence of egg allergy and even food allergies.
Dental Portable X-Ray,Handheld Dental X-Ray,Portable Dental Xray Unit,Portable Dental X-Ray Unit
Rolence Enterprise Inc. , https://www.rolencedent.com