Mark R. Etzel
Professor of Food Engineering, University of Wisconsin-Madison
Mark R. Etzel is a Professor of Food Engineering at the Univ. of Wisconsin-Madison in the Dept. of Food Science, and in the Dept. of Chemical and Biological Engineering (by courtesy). He obtained a BS at Purdue Univ., and a PhD at the Univ. of California at Berkeley, both in Chemical Engineering. His work on membrane technology for food protein separations began 15 years ago and is the subject of his presentation today.
To unlock the value of individual dairy proteins in milk and cheese whey requires a key technology –fractionation. This presentation will review the fundamental principles that govern fractionation of proteins in the dairy industrywhenusing membrane technology. Membranes are used routinely to concentrate dairy proteins. Concentration increases the protein content on a dry-solids basis in a mixture without changing the ratio of one protein to another. Fractionation does change the ratio of one protein to another but without necessarily increasing the protein-to-dry solids ratio. Fractionation is significantly more difficult to achieve than concentration when using membranes. It requiresa balancing act between permeating different proteins at substantially different rates through the membrane, minimizing deposit layer formation, altering dairy protein chemistry, and controlling permeate flux. With new membrane products and processes, making dairy protein fractions such as alpha-lactalbumin, beta-lactoglobulin, beta-casein, and glycomacropeptide is now possible. The range of new methods available to make these and other protein fractions using membranes, without chromatography, will be recounted. These new dairy ingredients will allow us to explore new domains for dairy, to seek out new markets and new applications, and to boldly go where no one has gone before.