Ion-exchange possibilities

When Davisco commercialized the ion-exchange technology about five years ago to manufacture its W.P.I. ingredient BiPRO, the company began applying the technology to isolate and purify other components of milk, including alpha-lactalbumin.

With the technology, Davisco produces W.P.I. with a leucine content of 13.1%, which is much higher than the 11% found in most W.P.I. ingredients. Leucine is the amino acid associated with promoting muscle health.

“BiPRO has an anabolic advantage over other W.P.I. ingredients because of its higher leucine content,” Ms. Olson said. “By using similar technology that allows for the higher leucine, we found we could isolate and purify alpha-lactalbumin.”

In the past, researchers could only produce about five grams of alpha-lactalbumin over the course of a week. Using ion-exchange technology, the company was able to commercialize production.

Isolation and purification of alpha-lactalbumin enables the development of infant formula that more closely resembles human milk.

“The scientific community quickly began ordering this product to evaluate its potential metabolic functions,” Ms. Olson said. “We could not fill orders.”

Today, filling orders is no longer an issue. The Jerome facility may produce more than one million lbs of alpha-lactalbumin annually, a 10-fold increase from just six months ago.

“It took us two years, and today we have a highly purified alpha-lactalbumin ingredient available in large quantities,” said Craig Sherwin, director of protein technology at Davisco.

With the ingredient, researchers may study its chemistry and identify opportunities for its use as a functional ingredient in foods.

“We know alpha-lactalbumin allows for the ‘humanizing’ of infant formula,” said Allen Foegeding, distinguished professor of food science at North Carolina State University, Raleigh, N.C., and editor-in-chief of the Journal of Food Science. “We now need to study its chemistry to identify other functions and applications. We learned that its unique 123-amino acid sequence produces a natural structure that denatures at a relatively low temperature (about 65°F) but the denatured structure is resistant to forming aggregates. This inhibits viscosity increases after heating, along with precipitation or gelation. Further, it makes denaturation highly reversible compared to other proteins.”

The functionalities make alpha-lactalbumin suitable for use in different types of beverages, providing other ingredients in the formulation do not favor aggregation.

Davisco manufactures cheese for a source of whey, which is where the alpha-lactalbumin is isolated from.

“The component we most want to isolate and harvest from whey — protein — is at a very low concentration,” said Lloyd Metzger, professor and chair of dairy education at South Dakota State University, and director of the Midwest Dairy Foods Research Center, Brookings, S.D. “Whey is primarily water and lactose. It is only about 0.8% total protein.”

He explained the differences and similarities of membrane filtration and ion-exchange technology, and how the two may be used in combination to isolate and purify desirable components of whey.

“Ion exchange yields protein fractions with fewer impurities,” he said. “The presence or absence of these impurities impacts (the) amino acid profile, as well as the ingredient’s solubility, heat stability, gelation and foaming properties.

“Only with ion exchange can you produce an alpha-lactalbumin isolate, an ingredient with more than 92% pure alpha-lactalbumin.”

When increasing the alpha-lactalbumin content of infant formula, the beta-lactoglobulin concentration decreases. This reduces viscosity and tendency to cause fouling during processing, a production perk.

And only Davisco has this technology, which Dr. Metzger helped develop.

The No. 1, and most immediate use for alpha-lactalbumin is as a protein ingredient in infant formula to more closely mimic the amino acid profile of human milk.

“The use of alpha-lactalbumin isolate enables the overall protein content of infant formula to be reduced, while still delivering essential amino acids to the infant,” said Mark Fenelon, head of the food research program at Teagasc Food Research Centre, Cork, Ireland. “In addition, in the manufacture of infant formula, alpha-lactalbumin displaces beta-lactoglobulin, thereby reducing viscosity and tendency to cause fouling during processing.”