Extrusion Processing of Amaranth and Quinoa into Gluten-Free Snack Foods for Celiac and Gluten-Free Diets

Because of the growth of gluten intolerance and Celiac disease, there is growing interest in development of gluten-free foods. Beyond just being gluten-free, such foods can also have other positive nutritional benefits to human health. Extrusion processing is commonly used to produce a wide variety of human food products. Gluten-free grains can be a processing challenge, however, due to lack of proper binding, which can lead to poor quality food products. This research explores how extrusion parameters impacted the quality of amaranth- and quinoa-based extrudates. The specific objectives of this project included extruding each of the grains, then measuring extrudate properties, such as color, unit density, expansion ratio, and durability. Both the quinoa and amaranth were extruded as raw grain, as well as ground to 2mm and 1mm particle sizes. Other experimental conditions included moisture contents of 20% and 40% (d.b.), and extruder screw speeds of 50 rpm and 100 rpm. All treatments were successfully extruded, and all extrudates had high quality attributes, making this the first time either quinoa or amaranth was extruded without any binding ingredients. This study provides information useful for commercial scale-up.