Egg consists of 56%~61% egg white and 27~32% egg yolk, which is rich in High-quality protein. Egg contain not only the eight essential amino acids needed by adults, but also the histidine that infants and toddlers must supplement through diet, in addition to containing carbohydrates, fats and trace elements. It is the natural food with protein biological value of 100.
However, eggs are one of the BIG 8 food allergens identified by the FAO/WHO. Studies have shown that egg allergy alone accounts for 35% of food allergies in children and infants, and 12% in adults.
The high-risk population of egg allergy focus on infants and children, and it is one of the causes of children secondary malnutrition. Adults who are born with certain genetic defects are also at risk for egg allergies. Egg allergy usually has clinically obvious eating or contact history. The main manifestations are skin symptoms, such as eczema-like rash, erythema, and son on. There also be abdominal pain, nausea and vomiting, respiratory asthma, etc. In severe cases, anaphylactic shock may occur.
Vaccine & Egg Allergy
Vaccination can cause severe allergic reactions for eggs allergy person, for example measles vaccine, flu vaccine, etc.
At present, most influenza vaccines are inoculating the virus on the chicken embryo, then extracting the chicken embryo infusion, then inactivating the virus, and finally collecting to make vaccine. The finished vaccine may be accompanied by a small amount of protein residue, which can cause some allergic reaction in an egg allergic person after vaccination. Therefore, people who are allergic to eggs should pay great attention to and take precautions when vaccinating them.
It is worth mentioning that COVID-19 (2019-NCOV), currently popular in the global environment, COVID-19 vaccine is being developed urgently. At present, at least seven different vaccines across three platforms have been rolled out in countries, and since the inactivated COVID-19 virus is produced by Vero cell, people with egg allergies who are vaccinated with the COVID-19 vaccine should not produce allergic reaction in theory.
In theory, any a kind of protein in egg can be allergens, however, it is generally believed that the eggs allergen is mainly found in the egg white, which contains about 40 different proteins. Among them, ovomucoid (Gal d 1), ovalbumin (Gal d 2), ovotransferrin (Gal d 3) and lysozyme (Gal d 4)were the most important allergen proteins, which can combine with human serum IgE and cause allergic reaction, the details are as follows.
Ovomucoid is a major allergen in egg white, accounting for about 11% of the total egg white protein. It is composed of 186 amino acid residues and contains 20% ~ 25% glycosyl. There is no free sulfhydryl in the molecule, but ovomucoid molecule contains 9 disulfide bonds with 28 kDa molecular weight. The glycosyl component makes the degradation and heat treatment of trypsin by ovomucoid quite stable. Moreover, the spatial structure of ovomucoid contains three independent homologous functional domains, which are successively arranged one after the other, and are respectively called the first functional domain, the second functional domain and the third functional domain, each functional domain is connected by intramolecular disulfide bonds. Studies have shown that the third functional domain of OVM has the strongest sensitization.
Ovalbumin accounts for about 54% of the total egg white protein, and is the most abundant in egg white. Ovalbumin has been widely used as a model protein in the study of protein structure, functional properties and animal models of food allergy. It has been reported that ovalbumin is not the most allergenic compared to other egg allergens. In addition, ovialbumin is a phosphoglycoprotein with 44.5 kDa molecular weight, which is composed of 385 amino acid residues and contains 3% glycosyl, and its molecule includes 1 disulfide bond and 9 sulfhydryl groups, the content of glycosyl is not high, and it is not resistant to heat and digestive enzymatic hydrolysis.
Ovotransferrin is an iron - binding glycoprotein with 76 kDa molecular weight, and has antibacterial activity in its free form, accounting for about 12% of the total egg white protein. The ovotransferrin is composed of 686 amino acid residues and contains 2.6%. There are 12 disufide bond in molecular, 2 domains in protein structure, respectively named N domain and C domain, each of them containing a ferric ion binding site, which makes ovaltransferrin possess many biological activities, such as antimicrobial activity, immunomodulatory activity and antioxidant activity.
Lysozyme also known as muramidase, whose chemical name is N-acetylmuramide glycanohydrlase, consists of a polypeptide chain. There are four disulfide bonds crosslinked in the molecule with stable structure. And lysozyme is acid and alkali resistant, accounting for about 3.5% of the total egg white protein. It has lysozyme activity, which can decompose gram-positive bacteria, but has no antibacterial effect on gram-negative bacteria, and is mainly used as bactericide, preservative and preservative in food processing. Meanwhile, lysozyme is one of the main allergens in egg white which has been reported recently.
There is no specific treatment for egg allergy, and strictly avoiding food contains eggs is the best choice for patients with egg allergy. Due to the diversity of food ingredients, the composition of food has become very complex, and it is difficult for patients with egg allergy to avoid harm. Therefore, it is necessary not only to find egg substitutes for high-quality protein in the diet, but also to accurately identify egg allergen protein in the production, processing and daily life. The Pribolab Egg Allergen Rapid Test Strip and the Pribolab Egg Allergen Test Kit can help us control the overall food production and daily food safety, ensuring egg allergy people health.
PriboFast®EggWhite (Ovomucoid) ELISA Kit
PriboFast®Ovalbumin ELISA Kit
PriboFast® Lysozyme ELISA Kit
PriboStripTM Egg Rapid Test Strip
Editor: Yan Sun, Food Engineering Master, Allergen Product Mgr, engaged in the validation and application support of allergen detection methods, has more than five years experience in food safety testing field.
Pribolab Pte. Ltd. founded in 2008, focusing on the R&D and sales of food safety diagnosis products. At present, Pribolab mycotoxin standard, stable isotope internal standard and other mycotoxin products have occupied a large market in the global scope. At the same time Pribolab has gradually expanded to the fields of marine toxin, GMOs, food composition analysis, food allergen, and it is stepping into the field of pharmaceutical and medical allergen.
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