We have known for some time that the egg has many valuable components with potential health benefits. Recently, various food scientists have reviewed the many egg proteins and lipid components having various bioactive applications including mine and Kovacs-Nolan, 2006 (Worlds Poultry Science Journal 62 No. 1: 87-95) and Anton et al., 2006 (Worlds Poultry Science 62 No. 3: 429-438).
Several egg white proteins are known to have antibacterial and biological properties. Lysozyme is effective against gram-positive bacteria and has antiviral activity. It has been used as a food preservative and various pharmaceutical applications. Lysozyme is routinely separated by the egg processing industry using ion-exchange resins.
Ovalbumin is the principle protein in egg white making up about 60 percent of the total egg white complex. Upon enzyme hydrolysis, the peptides formed have been observed to reduce blood pressure of hypertensive rats. Also, enzymatic hydrolysis of egg albumen has produced peptides which are effective for lowering blood pressure.
The protein ovotransferrin binds iron which inhibits growth of gram-negative bacteria. It has been proposed also for treatment of infants for acute diarrheas. Ovotransferrin and phosvitin from egg yolk both have the additional benefit of being an antioxidant, which relates to their iron-binding capabilities.
Avidin binds biotin making it unavailable to bacteria. Avidin binds to various gram-negative and gram-positive bacteria thereby producing antimicrobial activity. Some studies have also shown anticancer possibilities from Avidin. Enzyme hydrolysis of ovomucin has produced peptides, which have shown antiviral activity against Newcastle disease, bovine rotavirus and human influenza virus. The protein cystatin, which makes up about 0.05 percent of the egg white protein complex, has been observed to also have anticancer capabilities.
Omega-3 Fatty Acids
When considering lipid components, the industry is routinely marketing shell eggs which are enhanced with omega-3 fatty acids. Omega-3 fatty acids are known to be an essential nutrient for brain function, eye health and prevention of heart disease. Phosphatidylcholine (lecithin) is a primary lipid found in egg yolk. Choline is known to be important for brain function. Some research has indicated that yolk phospholipids such as lecithin may alleviate symptoms of Alzheimer disease. There has been some interest in sources of egg lecithin.
Thus, there are several components of eggs that may have health benefits. There is a need of further research on economical and practical methods to fractionate these various components from eggs. Utilization of the various egg fractions for health applications would open new value-added opportunities to our egg processing industry.