Technical Talk: August-September 2013 – Eggs-cellent eggs

Eggs and egg ingredients have been, and continue to be, used widely in the manufacture of baked goods.

Eggs and egg ingredients have been, and continue to be, used widely in the manufacture of baked goods. As ingredients they provide two basic functions: nutrition/health benefits and functionality.

Eggs are a rich nutrient source. They contain high-quality protein and a balanced amino acid profile. They contain a variety of essential vitamins and minerals and a number of health-promoting natural chemical compounds, including lutein and zeaxanthin (which are thought to help prevent cataracts and age-related macular degeneration). Eggs also are rich in choline, which plays a role in memory development.

Eggs contain particular proteins and emulsifying agents that provide value and functionality in food formulation. The extraction of these components, and what effect processing has on their behaviour, is a large area of research. In particular, egg proteins like ovalbumin and albumen are of interest due to functional properties such as foaming capability. Egg albumen and egg yolk are sources of different proteins. Egg yolk contains useful lipids, including specific compounds like lysozyme, cystatin, ovotransferrin, and yolk phospholipids such as lecithin. 

Though eggs contain cholesterol, their nutritional value and functionality in formulations far outweigh this negative effect. High blood cholesterol is linked to a higher risk of heart disease, and since egg cholesterol is in the yolk, pasteurized liquid egg whites have gained some popularity as have egg substitutes. Still, eggs have taken a hit to their image. The recent addition of omega-3 fatty acids has boosted their use.These fats are mainly found in fish, but for consumers who do not consume fish, eating omega-3-enriched eggs is a convenient alternative.

The close proximity in which eggs are mass-produced may result in a greater incidence of salmonella and other pathogenic bacterial contamination. There were increasing numbers of these outbreaks in the past, some of which were associated with the consumption of raw or lightly cooked eggs. Even intact, clean, Grade A eggs may contain salmonella because the shell is porous enough for the bacteria to enter. Egg producers are taking more precautions to minimize contamination and new technology is being developed to eradicate salmonella and other pathogens. The effect of heat, ozone, microwave, irradiation, pulsed electric field and hydrostatic pressure treatments on bacterial count reduction are being looked at as a means of inactivating pathogens.

The bakery industry is familiar with using eggs as ingredients in various forms. Small operations are still using shell eggs. However, such usage is inconvenient for large production facilities and poses more food safety risks. The three major egg ingredients available for commercial use are whole, yolk and whites. Whites are also known as egg albumen. These three types are available fresh (refrigerated), frozen or dried. The functionality of these basic types in baked goods is distinct due to their difference in composition. Whole eggs provide the full complement of functionality but using the other components individually provides enhanced specific functionalities. For example, egg yolk, due to its fat content and other lipid components such as lecithin, has elevated emulsification properties. On the other hand, egg whites, due to the protein composition, provide superb foaming capabilities as well as leavening action. The most convenient and safest way to use the three major egg ingredients is in the dry format, which is much easier to handle and poses far fewer food safety risks. Dry egg ingredients allow the manufacture of complete bakery mixes without the inconvenience to the baker of adding eggs.

The functionality of eggs and their ingredients can also be enhanced by the use of specific enzymes. Egg processing enzymes that improve yield and quality, accelerate processing times and maintain consistency are available from various enzyme manufacturers. They provide a range of products that specialize in different areas of need: removal of hydrogen peroxide, removal of contaminating fat from egg white, egg white browning prevention, improvement of egg white foaming capacity, improvement of egg yolk emulsification properties, etc. For example, the use of a specific lipase in egg yolk processing results in much higher emulsification properties that may allow the manufacture of good quality mayonnaise with much less fat content. Enzymes may also be used for the production of egg white hydrolysates as a protein source for sports and nutritional products that has a bland taste and is more digestible than whey.  

The egg’s complexity and its extraordinary functional properties make it very difficult to develop good alternative replacement ingredients.

For more information, or fee for service help with food technical and processing issues and needs, please contact Dr. John Michaelides at John Michaelides & Associates at 519-743-8956 or at Bioenterprise  519-821-2960 ext. 226, by e-mail: j.jmichaelides@gmail.com. Bionterprise is a company of experienced professionals that coach and mentor emerging Agri-technology companies to profitability and beyond.