The effect of the amylose content and milling fractions on the physico-chemical features of co-extruded snacks from corn

The suitability of corn fractions (break meal: 250–500 µm; flour: < 150 µm) from hybrids with different amylose contents (conventional: 18%; high-amylose: 42%; waxy: 2%) and their blends, to produce co-extruded snacks was assessed. Corn flour exhibited a higher content in total soluble phenolic acids (+34%) than break meal. The high-amylose hybrid maintained a higher antioxidant capacity and phenolic acid content (+52% for soluble and + 54% for cell-wall bound phenolic acids), even after extrusion, than the conventional one. Because of its gelatinization properties (high pasting and peak temperatures; low maximum viscosity), the high-amylose hybrid produced co-extruded snacks characterized by low section areas and large inner areas. The blends led to snacks whose features (sections and inner areas, porosity and hardness) did not follow a linear trend with the amylose content, suggesting the need for further studies to better understand the starch interactions that take place among the various hybrids.