Optimization of extrusion parameters to decrease resistant starch in extruded corn crude starch

Resistant starch type Ⅲ was produced in extruded corn crude starch cooling to ambient temperature. In order to reduce the influence of resistant starch type Ⅲ on dextrose equivalent value of liquefied and saccharified starch extrudate, the system parameters of the extrusion needed to be optimized. In this paper, a five-variable, five-level quadratic orthogonal rotating combinational design was employed to achieve the aims of this experiment. The influence of extrusion system parameters on resistant starch type Ⅲ content was studied. The optimized extrusion parameters were as follows: the barrel temperature 60.0℃, the moisture content of feed 27.0%, the nozzle diameter 11.0 mm, the screw speed 200.0 r·min-1, the gap of spindle nose 10.0 mm. Under those conditions, the resistant starch type Ⅲ content was 1.48%.