Conquering egg allergenicity without compromising functionality: review

The summary, published in the Journal of Agricultural and Food Chemistry,​ looks at recent advances in understanding egg allergens achieved by joint efforts between regulatory bodies, food industrials and scientists. There is no sufficient remedy for allergy sufferers apart from avoidance of the product, made difficult by its extensive use in the food industry. Research has therefore dominated two areas. Firstly, manufacturers seek the production of hypoallergenic egg-containing products, as the total absence of a specific allergen from food products is often difficult to achieve. "A main obstacle to the use of food processing in reducing egg allergenicity is the risk to alter the unique functional attributes of egg proteins,"​ note the authors of the review, Yoshinori and Yang from the University of Guelph. ​Secondly, there has been progress in the development of test kits for detecting egg-derived contaminants so manufacturers can correctly communicate allergen information to the consumer. ​The report said: "Quantification methods in food analyses are necessary to comply with legal requirements such as food labelling but also, more importantly, to ensure protection of food-allergic consumers." ​​Egg allergy problem ​​Egg-derived components are widely used in the food industry, particularly in processed foods where they are often used as emulsifiers or gelling agents. However, egg allergy has an estimated prevalence of between 1.6 per cent and 3.2 per cent making it the second most common cause of food hypersensitivity in children. In some industrialised countries, it is thought to be the most prevalent food allergy among children. The cause of the problem, like most other food allergies, is protein, present mainly in the egg white. The main culprits include ovalbumin, ovomucoid, ovotransferrin and lysozyme. ​Developing hypoallergenic egg products ​​A number of studies have looked at using food processing methods to reduce egg allergenicity without compromising the functionality of the product. One process is thermal processing, which is normally carried out to enhance texture and flavours or to guarantee microbiological safety. Enzymatic processing is described in the review as a more "specific approach".​ This is quite efficient in producing milk-based hypoallergenic formulas, but faces a major hurdle in maintaining the foaming and gelling properties of the product. However, a recent study found positive results using a combination of thermal treatments and enzymatic hydrolyses, which did not alter the functional properties, therefore presenting potential for use in the industry. Other processes explored by researchers include radiation technology and novel food processing methods, such as high pressure and pulsed electric field. The authors wrote: "The current understanding of egg allergens offers novel approaches toward the making of food products safe for human consumption and the development of efficient immunotherapeutic strategies." ​ Detecting egg allergens ​ The review said analytic methods for the detection of egg and other food allergens should provide specific, sensitive, and rapid analyses. Methods include diffusion-in-gel techniques, antibody-based methods, electrophoretic and blotting methods, and the use of polymerase chain reactions. Immunotherapeutic approaches ​​Research has led to an increasing understanding of the relationship between intestinal microflora and immune disorders, and probiotic bacteria have been found to provide immunomodulatory capacities. The advantages of using prebiotics in parallel with probiotics have also been explored, using ovalbumin as surrogate allergen. Additionally, antioxidant compounds naturally present in foods may also have similar effects in favour of allergy inhibition. Source: Journal of Agricultural and Food Chemistry​ June 2008, Doi: 10.1021/jf8001153 "Recent Advances in the Understanding of Egg Allergens: Basic, Industrial, and Clinical Perspectives" ​Authors: Yoshinori Mine and Marie Yang