Effect of amylose/amylopectin ratio and extent of processing on the physical properties of expanded maize starches

Summary Low‐density expanded starchy products are often desirable, particularly in the snack food industry. Levels of shear and amylose deemed crucial factors for expansion. In this study, maize starches containing low (waxy), normal high levels were compared after processing. Low processing used a popping head (similar to rice‐cake machine), while (~450 kJ kg −1 ) samples (pellets directly expanded) created using twin‐screw thermomechanical extrusion. Native ground extruded materials (<106 µm) popped same conditions (230 °C, 4 s, water content 12% wwb). All tested fused aerated cakes, which had little or no remaining crystallinity, except waxy sample, retained ~17% its original crystallinity. Water absorbances solubilities influenced greatly by starch source marginally amount On processing, showed increased solubility those with greater absorption. The densities all similar despite marked differences regime history major variations amylopectin ratios. These results challenge expected relationships between different starches’ potential expand.