Whey, a watery-byproduct of cheese making, was at one time considered waste and used as animal feed. Whey contains mostly lactose and a small amount of protein. Whey protein contains alpha-lactalbumin, beta-lactoglobulin, bovine serum albumin, heavy and light - chain immunoglobulins(Igs), and proteose-peptones. With the introduction of membrane technologies, excess water was removed from whey, concentrating the whey protein and lactose, along with smaller amounts of minerals, and milkfat. The concentrated product, known as whey protein concentrate (WPC), may contain from 35 to 85% protein. Whey protein isolates (WPI), obtained by ultrafiltration followed by ion-exchange, contain over 90% protein.

The functional properties of WPC and WPI may be variable because of different manufacturing techniques or because of varying amounts of lactose, minerals and fats. Their functional properties are mainly those of the whey proteins, alpha-lactalbumin and beta-lactoglobulin, in combination. Isolating the proteins would extend the functionality range for these proteins. Alpha – lactalbumin may find use in infant formulations for creation of humanized formulas or in various drinks, such as sports or health drinks, as a protein supplement and emulsifier. Beta-lactoglobulin may find application in edible films or as a gelling agent.

A new process was developed for separating the proteins in WPC containing 75% protein, using high-pressure or supercritical carbon dioxide. The process results in enriched protein fractions of alpha-lactalbumin and beta-lactoglobulin. The fractions can be recovered by microfiltration or centrifugation followed by ultrafiltration steps for individual recovery of the proteins. The process is environmentally friendly. No contaminating salts, solvents, or acids remain after depressurization.

Infant formulations with isolated alpha-lactalbumin may
help produce bright, cheery babies like this one.

Patent Status:
U.S. Patent 5,925,737, issued July 20, 1999.
Samples may be provided through a Material Transfer Agreement.

Responsible Scientist/Engineer:
Dr. Peggy M. Tomasula
Eastern Regional Research Center
USDA, ARS
600 E. Mermaid Lane
Wyndmoor, PA 19038
e-mail: Peggy.Tomasula@ars.usda.gov  

Technology Transfer Contact:
Victor (Vic) Chavez
(215) 233-6610
e-mail: vic.chavez@ars.usda.gov