Volume, firmness and crumb characteristics of gluten-free bread based on extruded quinoa flour and lactic acid

Abstract

Coeliac disease forces on the developing of gluten-free products. Gluten-free cereals may be modified by techniques like cooking-extrusion or by adding compounds like lactic acid in order to obtain mixtures with adequate viscoelastic properties for the developing of baked products. The present work studies the elaboration of gluten-free bread with extruded quinoa (Chenopodium quinoa Willd) flour and lactic acid. The influence of feeding humidity (18% and 25%) and temperature of extrusion (60 °C and 95 °C) on water absorption index (WAI) and water solubility index (WSI) of extruded flours was investigated. The results showed that feeding humidity led to changes on WAI. Baking process was studied by varying the amount of lactic acid added during bread baking. The specific volume, firmness and crumb characteristics (average cell size and cell number per mm2) of bread were determined. A control sample based on commercial gluten-free flour and no lactic acid was used. The results showed that lactic acid content did not affect bread firmness. Bread prepared with extruded flours at 95 °C, 25% feeding moisture had higher firmness (p < 0.05) than bread prepared with other extruded flours and control sample. Low level of lactic acid (0.2%) led to bread with high specific volume. The use of an extruded quinoa flour with low levels of lactic acid led to a gluten-free bread with a high specific volume and low firmness.