June 23/Wyndmoore, Pa./Food Business Week -- "Adding whey protein concentrates or isolates to expanded snack foods would boost their nutritional content; however, adding non-textured whey proteins in amounts larger than 5% interferes with expansion, making the products less crunchy. To counter this effect, whey protein isolate (WPI) was first extruded (texturized) at either 50C (WPI-50) or 90C (WPI-100) before adding to corn meal at 25% (WPI) level and was extruded again to make the puffed product," scientists in the U.S. report.

"Corn meal, corn meal with non-texturized WPI (25%), corn meal with WPI-50, or corn meal with WPI-100 were extruded at high shear conditions (300 rpm) and product temperatures of 125C. All extrudates containing texturized WPI were more expanded, firmer, crispier and easier to break than corn meal or corn meal with non-texturized WPI," wrote C.I. Onwulata and colleagues, Department of Agriculture.

The researchers concluded, "Pre-texturizing whey proteins and using them in extruded snacks improves textural properties, making it possible to add large amounts of whey proteins directly into expanded snacks to fortify them."

Onwulata and colleagues published their study in the Journal of Food Processing and Preservation ("Use Of Extrusion-texturized Whey Protein Isolates In Puffed Corn Meal." Journal of Food Processing and Preservation, 2010;34(Suppl. 2):571-586).

For additional information, contact C.I. Onwulata, Agriculture Research Service, Dept. of Agriculture, Eastern Reg Research Center, Dairy Processing & Prod Unit, 600 E Mermaid Lane, Wyndmoor, PA 19038, USA.

From the July 6, 2010, Prepared Foods E-dition