Research and technology investments have enabled the U.S. dairy industry to launch a variety of high-value protein ingredients, including whey protein concentrates (WPC) ranging from 34-90% protein and whey protein isolate (WPI), which is more than 90% protein. WPI and WPC are the most functional of all whey ingredients.
Whey proteins can be formulated into many foods for added function, nutrition and flavor, but it’s important to choose the appropriate ingredient.
Athletes have long known that whey proteins support muscle recovery, weight management and satiety. Whey proteins are high in quality because they are a complete protein, containing all of the essential amino acids. But everyone from children to aging adults can benefit from these attributes.
Mild flavor is a primary advantage of whey proteins over alternatives. They can enhance existing flavors or add flavor. For beverages and confections, whey’s flavor exposes fruit and chocolate flavors. In soups and sauces, spices and herb flavors are accentuated.
One of the most unique properties of WPC and WPI is solubility over a wide pH range (2 to 9). Protein solubility depends on water-binding capacity and physical state. WPCs are very soluble but have low water-binding capability, making them well-suited for sports beverages or meal replacement applications. However, solubility is affected by heat, so it’s important to know the ingredient’s temperature and pH limits to prevent denaturation or partial solubility loss.
Water-binding and viscosity
Water-binding and viscosity are related functions — products that bind large quantities of water create viscosity. A protein’s structural bonds break when heated, causing the molecule to unfold. This creates additional water-binding sites, increasing the solution’s viscosity. In nutritional beverages, low water-binding and viscosity allow incorporation of higher protein levels without hindering visual appeal, taste or texture.
Under specific conditions, unmodified whey proteins form irreversible gels. Gels formed in 3-5% protein-concentrated solutions at 55-70 degrees Celsius are more translucent and softer, and more opaque gels are formed when 10% protein-concentrated solutions are heated to 90-100 degrees Celsius.
Overall, gels tend to be opaque and weak in acidic conditions and more translucent and elastic in neutral and basic solutions. This unique capability of whey proteins helps maintain moisture in baked goods and meats and improves texture and mouthfeel in reduced-fat applications and puddings. WPI delivers high clarity and low turbidity.
WPC and WPI have both hydrophilic (water-attracting) and hydrophobic (water-repelling) groups. Whey proteins form membranes around oil or water globules by absorbing at the oil/water interface. At this point, the proteins partially unfold to stabilize the globules and prevent oiling off.
The stability of whey protein emulsions can be further enhanced by adding gums or heating the system to create a protein gel. These emulsification properties are useful in many processed food products.
Whipping, foaming and aeration
The speed of air incorporation and the stability of whey protein foams are dependent on a number of parameters: total solids, protein, carbohydrate and calcium concentrations, pH and whipping method. Good whipping and foaming properties are crucial in whipped toppings, ice cream and frozen yogurt, marshmallow, nougat and icings. Whey proteins can be used to partially replace or extend eggs in bakery products.
As research continues, increasingly functional and customized whey protein ingredients will become available. Visit ThinkUSAdairy.org for the latest information, including technical reports about using whey proteins.