USE OF EXTRUSION-TEXTURIZED WHEY PROTEIN ISOLATES IN PUFFED CORN MEAL

ABSTRACT 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. 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. 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. PRACTICAL APPLICATIONS This study determined that it is better to modify whey protein isolates (WPI) before adding them to the corn meal and extruding them to create crunchy products. The process described shows that modifying the structure of the whey proteins creates a form of WPI that is more compatible with corn meal. This knowledge allows the creation of nutritious high-protein expanded crunchy snacks.