Formulating with Whey Protein

Whey has come a long way from its beginnings as a valueless cheese byproduct used as animal feed. As Lynn Kuntz, editor-in-chief, pointed out in an article for Food Product Design, whey delivers high nutritional value as well as a range of functional properties that prove valuable in many nutritional products.

Whey proteins comprise about 18 percent of the protein in cows milk, primarily as lactalbumin and lactoglobulin; liquid whey  contains proteins, peptides, lactose, milkfat and other lipis; mineral salts and ions; vitamins; and water. After removing the water and concentrating the whey proteins, the whey protein isolate (WPI) delivers 90 percent or more protein, although manufacturing technology can affect the composition and functional properties of the WPI. Use of enzymatic hydrolysis can also alter the functionality of WPI.

As a functional ingredient or supplement, WPI supplies high-quality concentrated protein, delivering all 20 amino acids, including high concentrations of amino acids such as glutamine and leucine that are metabolized at high rates during exercise. It also has a low content of fat and lactose, and is fairly clear and heat stable, allowing its use in applications such as protein waters, isotonics and protein shots. It is soluble or forms a stable colloidal dispersion at ambient temperature and under all pH conditions.

However, there are certain formulation considerations. Eric D. Bastian, Ph.D., vice president, research & development, Glanbia Nutritionals, noted: A WPI rich in beta-lactoglobulin would be suitable for a high-gel product because beta-lactoglobulin has a strong gelling protein. Glycomacropeptide triggers hormones that may signal fullness and act as a satiety peptide. As a result, MF WPI could be used in a weight-management product. Formulators using WPI need to understand these two major types of WPI and examine their functional differences in specific applications, such as protein bars and ready-to-drink beverages.

While WPI is very stable across the entire food pH range, in clear beverage applications, which are generally hot-fill beverages, the pH needs to be around 3 to maintain good stability and solubility, Bastian said. Smoothies, which also require heat, can be made at higher pH levels, but above pH 4.0 to 4.5, specialized processes and stabilization systems need to be utilized for maintaining stability. Neutral pH is also a region that is generally unstable for WPI in heated applications like beverages, so stabilization systems are important.