Instrumental and sensory characteristics of a baked product containing barley flour with varying amounts of beta-glucan and sugar substitute

Abstract

The objective of this study was to determine the influence of varying levels of beta-glucan in barley flour on selected properties of a model baked product. Another aim was to reduce sugar levels in the product by incorporating a natural sweetener stevia and to monitor its influence using instrumental and sensory analysis. Batter rheology was studied using a lubricated squeezing flow technique, pasting profiles of the barley flours were determined with a rheometer, viscoelastic properties were evaluated using dynamic oscillatory rheology to measure G’ and G”, and firmness of the baked products was monitored using a texture analyzer, for changes occurring due to varying β-glucan levels in barley flour and removal of sugar. L a* b* color values of barley flour and muffins were obtained using a colorimeter. A descriptive sensory panel was trained to observe changes in product attributes when stevia was used to replace sugar in the high betaglucan product. Water absorption index was found to be significantly higher for high β-glucan barley flour. The color of both barley flours also had a significant difference in L* (lightness) and b* (yellowness) values. Similarly, muffin samples prepared without sugar, using stevia, were significantly lighter in surface color (higher L*), while the interior colors were darker (higher b*). Low beta-glucan dough showed a lower biaxial extensional viscosity compared to the high beta-glucan dough, which indicates that the level of beta-glucan present in the barley flour has an impact on the dough viscosity. The pasting profiles of the flours were also found to be significantly different, where the high beta-glucan barley flour resulted in a significantly higher peak viscosity but lower peak time compared to low β-glucan barley flour. Muffin firmness was found to be significantly higher when sugar was omitted from the formulation, but there was no significant difference in firmness among the two beta-glucan levels in the muffins. The sensory descriptive panel found significantly higher firmness, surface roughness, and bitterness attributes for the high β-glucan muffins prepared with stevia. Additional efforts will be needed to mask the undesirable attributes in the model baked product occurring due to the removal of sugar.