How Make Great Egg White Foam
Eggs are a mainstay in the American diet (and many around the world). Their functional properties such as binding, emulsion, and structure make them a useful addition to many food products. Beating the whites of the eggs until they expand and foam contributes to many desserts and baked goods. The purpose of this experiment is to gain experience preparing and identify the factors in egg white foams.
Keywords: Egg White Foam, Sugar, Cream of Tartar, Food Industry, Functional Food
Effect of Acid and Sugar on Egg White Foams
Eggs are common ingredients employed by the food industry for their thickening, gelling, emulsifying, foaming, coloring, and flavoring properties, as well as their moderate calorie content, excellent protein, rich fat-soluble compounds, and low economic cost (Miranda, 2015). They are said to be “polyfunctional,” and it is important for the food industry to fully understand the functional properties of egg proteins to develop new products (Soderberg, 2013).
Foams are two-phase systems, where gas bubbles are dispersed and suspended in liquid (Ptaszek, 2014). The capacity of egg white proteins to be beaten into a foam that increases to six or eight times its original volume is used to aerate and leaven a number of food products, such as puffy omelettes, souffles, angel food cake, sponge cake, and meringues; it is invaluable in food preparation (Brown, 2015).
Denaturation is the process whereby physical or chemical changes destroy the stabilizing structures of protein (Bettelheim, 2010), causing the protein molecules to unfold, uncoil, and stretch out. Egg white foams stabilize by the denaturation of their proteins, which then form a protective coating around air bubbles whipped into the liquid egg white (Walter & Beathard, 2015).
However, proteins that unfold due to mechanical beating eventually start to regenerate their initial shape, and this is manifested by foam vanishing and draining. Until recently, mono- and disaccharides were the most popular systems used in foam stabilization. Nowadays, due to an increasing interest of consumers in low-sugar food products, alternative stabilizing agents are considered (Ptaszek, 2014).
The purpose of this experiment is to identify the factors contributing to volume and stability in egg white foams and gain experience in the preparation of egg white foams.
According to the lab manual Understanding Food Principles and Preparation, adding an acid to an egg white foam produces a stable foam, and sugar also produces a stable foam when added near the end of the whipping process (Walter & Beathard, 2015). Therefore, I hypothesize that egg white foams made with acid (cream of tartar) and with sugar added at the end will produce the stable foams.
1 fresh, large egg, room temperature
- Separate egg white and yolk.
- Beat the egg while at room temperature with an electric mixer on high speed until just the tip of the peak bends over as the beater is lifted from the foam (stiff peak stage).
- Record the time required to beat the foam to stiff peak stage.
- Remove ¼ c. of foam and float on ½ inch (1.5 cm) of hot water in an 8×8 inch baking pan. Bake at 350 *F until the egg foam turns brown (~15 min.). Cool and record description.
- Measure the remaining foam and record the volume of the foam using a glass graduated measuring cup.
- Record the appearance of the whipped foam.
- Use a funnel liner to line a funnel that is supported in a graduated cylinder. Place the whipped foam into the lined funnel.
- Record the volume of filtrate in the cylinder at 15-minute intervals for one hour.
- Record any change in the appearance of the whipped foam.
- Control – Prepare egg foam according to the basic recipe.
- Added sugar – Prepare egg foam according to the basic recipe, except add 2 T. granulated sugar gradually at the soft peak stage (peaks fall over as the beater is lifted from the foam). Then complete beating to the stiff peak stage.
- Added acid – Prepare egg foam according to the basic recipe, except add ¼ t. cream of tartar at the foamy stage (mixture is fluid and has many bubbles on the surface). Then complete beating to the stiff peak stage.
- Splenda® – Prepare egg foam according to the basic recipe, except add 2 T. Splenda® gradually at the soft peak stage (peaks fall over ass the beater is lifted from the foam). Then complete beating to stiff peak stage.
- Added egg yolk – Prepare egg foam according to the basic recipe, except add ½ t. egg yolk to the egg white before beating.
- Dry stage – Prepare egg foam according to the basic recipe, except over-beat until the foam is dry and appears dull and curdled.
The hypotheses that an egg white foam made with cream of tartar, an acid that lowers the pH, would produce a stable foam was supported by the data. This is consistent with Bovskova and Mikova, who found that the largest volume and the lowest drain were observed with egg whites at pH 4, and from pH 6.5 to 7.0, which is below the pH range from 7.5 to 8.5, the common pH of egg whites (Bovskova & Mikova, 2011).
The hypotheses that the egg white foam with sugar added at the end would produce a stable foam was also supported by the data. This is also consistent with Bovskova and Mikova, who found that the addition of saccharose (sucrose/table sugar) increased the durability of the foam at concentrations above 2%, and the durability of foam increased with increasing saccharose (Bovskova & Mikova, 2011).
The results and the existing literature agree: adding cream of tartar decreases the pH of the foam, enhancing the uncoiling process, and adding sugar near the end of the whipping process absorbs some of the water, preventing further denaturation, both of which produce a stable foam (Walter & Beathard, 2015).
However, there is a limitation to this conclusion. Each variation was tested by a separate group, who were given one egg to observe. One egg does not have enough volume to be beaten the countertop standing mixers in the school laboratory, so every group used a hand tool. This was not discussed or standardized among the groups, allowing some to use a simple whisk and others to use a mechanical beater. This difference skews the timing of each experiment, makes that data unreliable and may contribute to the deviation in the results.
One deviation in the results is that the time to beat the control method reached stiff peak stage in significantly less time (3:45) than to beat with cream of tartar added (19:00). Given that the addition of acid lowers the pH and enhances the uncoiling, it was reasonably expected that method would be the quickest.
Another deviation is the control method time to stiff peak stage (3:45) was longer than to reach dry phase (3:40). Given that, when beating an egg white foam, the stiff peak stage comes before dry phase, it was reasonably expected that the stiff peak stage would take less time to reach and the dry phase would take the longest.
The last deviation is that many groups either didn’t record or didn’t share their observations from the cooked foam. Therefore that data is missing.
Considering that the worldwide production of eggs increased in recent decades and exceeded 64 million tons in 2009, the addition of stable egg white foam into products could be an important way to value the products and to gain profitability for egg producers and the food industry (Miranda, 2015).
Bettelheim, F. A. (2010). Introduction to Organic and Biochemistry, Eighth Edition. Belmont: Brooks/Cole.
Bovskova, H., & Mikova, K. (2011). Factors Influencing Egg White Foam Quality. Czech Journal of Food Science, 322-327. Retrieved from http://www.agriculturejournals.cz/publicFiles/44989.pdf
Brown, A. (2015). Understanding Food Principals and Preparation. Cengage Learning.
Miranda, J. M.-V.-S. (2015). Egg and Egg-Derived Foods: Effects on Human Health and Use as Functional Foods. Nutrients, 706–729. Retrieved from http://doi.org/10.3390/nu7010706
Ptaszek, P. Ż. (2014). The Physical and Linear Viscoelastic Properties of Fresh Wet Foams Based on Egg White Proteins and Selected Hydrocolloids. Food Biophysics, 76–87. Retrieved from http://doi.org/10.1007/s11483-013-9320-5
Soderberg, J. (2013). Functional properties of legume proteins compared to egg proteins and their potential as egg replacers in vegan food. Swedish University of Agriculture Sciences. Uppsala, Sweden. Retrieved from https://stud.epsilon.slu.se/6240/7/soderberg_j_131101.pdf
Walter, J. M., & Beathard, K. (2015). Understanding Food Principles and Preparation, 5th Edition Lab Manual. Stamford, CT: Cengage Learning.