Effect of extrusion cooking on the physical-chemical properties of whole kiwicha (Amaranthus caudatus L) flour variety centenario: Process optimization

Abstract Kiwicha (Amaranthus caudatus) is a gluten-free pseudocereal, regarded as a good source of high-quality protein and fiber. The use of whole flours is of interest for obtaining healthy extruded snacks but the Sectional Expansion Index (SEI) can decrease. The aims of the study were to: a) evaluate the effect of initial moisture and extrusion temperature using a face-centered central composite design on the physical-chemical properties of kiwicha whole flour such as water activity, SEI, density, water absorption index, Water Solubility Index (WSI), color, texture (hardness and shear strength), gelatinization degree, pasting properties, thermal properties, total phenolic (TP) and antioxidant capacity by DPPH (AC-DPPH) and ABTS (AC-ABTS) and b) optimize the extrusion cooking using response surface methodology maximizing SEI, WSI, TP, AC-DPPH and AC-ABTS. The extrusion cooking parameters influenced on physical-chemical properties of extruded kiwicha. The optimal condition was extrusion temperature of 190 °C and 14% initial moisture and extrudates showed 7.17 SEI, 61.5% WSI, 101.2 μmol trolox/g AC-DPPH, 364.2 μmol trolox/g AC-ABTS and 34.5 mg GAE/100 g TP.