pH Stability

The functional definition of pH is the measurement of the acidity or alkalinity of a solution commonly measured on a scale of 0 to 14. pH 7 is considered neutral with lower pH values being acidic and higher values being alkaline or caustic. PH is the most common of all analytical measurements in industrial processing

  • To produce products with consistent well-defined properties
  • To effectively produce products at optimal cost
  • To avoid causing health problems to consumers
  • To meet regulatory requirements1

While whole eggs are relatively pH neutral, egg white is one of the few food products that is naturally alkaline, with an initial pH value that can be as low as 7.6 at time of lay, but with increasing alkalinity as the egg ages, and can reach pH of 9.2.2 Factors that can influence the pH of the egg include the age of the hen at the time of lay. The pH of a fresh egg yolk is about 6.0 and increases to 6.4 to 6.9 during storage. Storage at refrigerated temperatures greatly slows the pH change and helps reduce the rate of the thick egg white from thinning. In general, the egg pH is stable and does not disrupt food product formulations.3

In terms of foaming, a key functional benefit of egg white in particular, proteins create more stable foams at a pH that is near 7.0 and are less functional as that number rises to 9.0. In order to help stabilize egg white foam, a common approach is to add cream of tartar, which lowers the pH of the egg white and shortens the time necessary to produce a foam.4

1. Queeney K. (2007). The Importance of pH Measurement in Assuring Product Quality, Food Manufacturing magazine, Advantage Business Media, Rockaway, New Jersey, USA http://www.foodmanufacturing.com/article/2007/06/importance-ph-measurement-assuring-product-quality (accessed May 19, 2017)

2. Brown A. (2011). Understanding Food: Principles and Preparation, Fifth Edition, Cengage Learning, Stamford, Connecticut, USA

3. Stadelmen WJ and Cotterill O.J (1995). Egg Science and Technology, Fourth Edition, Haworth Press, Inc., New York, USA

4. Aeration in Baked Goods: Using Eggs to Create Foams, National Egg Products School, McKee, S. Auburn University, Alabama

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