Putting fruit through the extruder
Snack foods made by extrusion can boost their antioxidant content and dietary fiber profile by adding fruits and vegetables to their formulations. More specifically, apples do the job well, according to researchers from the Department of Grain Science and Industry at Kansas State University, Manhattan, KS, working with colleagues from J.R. Short Milling Co., Kankakee, IL, and the National Engineering School of Agronomy and Food Sciences at Nancy, France.
Researchers sought to improve the nutritional value of extruded and expanded ready-to-eat snacks and breakfast cereal products. They blended corn flour with apple pomace, the solids remaining after juice is extracted. Experimenting with addition rates of up to 28%, they reached total dietary fiber levels as high as 22.5%. The mixtures were then put through a cooker-extruder equipped with an expansion die.
Use of apple pomace increased nucleation and resulted in higher mechanical strength for the finished product. They tested for antioxidants and found that content decreased but activity actually increased.
The study was reported at the 2011 annual meeting of AACC International.