Optimization of Extrusion Conditions for a Gluten-Free Snack Produced from White Quinoa (Chenopodium quinoa W.)

This study optimized the extrusion conditions for the development of a gluten-free snack produced from white quinoa flour (Chenopodium quinoa Willd.), integrating the physicochemical characterization of the raw material with a multi-response evaluation of the critical processing parameters: screw speed, outlet temperature, and feed moisture content. The flour exhibited an average proximate composition of 10.73% moisture, 2.11% ash, 14.07% protein, 5.13% fat, 3.14% fiber, and 64.83% carbohydrates, demonstrating its technological suitability as an amylo-protein matrix for expanded products. Optimization was performed using Response Surface Methodology (RSM) through a face-centered Central Composite Design comprising 16 experimental runs, within ranges of 200–400 rpm screw speed, 120–150 °C outlet temperature, and 15–20% moisture content. Physical, functional, colorimetric, and textural responses were evaluated, including expansion index, degree of gelatinization, water absorption index, bulk density, porosity, volume, CIELab color parameters, and texture attributes. The results showed that the interaction among temperature, moisture content, and screw speed markedly modulated structural expansion, starch gelatinization, and the mechanical behavior of the extrudates. The expansion index ranged from 4.695 to 6.085 mm, the degree of gelatinization from 57.99 to 97.84%, the water absorption index from 3.58 to 6.72 g/g, and bulk density from 0.063 to 0.110 kg/m³. The condition of 300 rpm, 150 °C, and 17.5% moisture stood out by achieving the highest expansion, high gelatinization, low bulk density, and greater volume, resulting in a more aerated and potentially crisp product structure. Multi-response optimization yielded an overall desirability of 0.673, confirming the feasibility of the RSM approach for establishing suitable technological conditions for producing value-added, gluten-free expanded snacks from white quinoa.