The effect of the ultrasound process and pre-gelatinization of the corn flour on the textural, visual, and sensory properties in gluten-free pan bread.

The present study used ultrasound waves with the intensity of zero, 30, and 70%, as well as the microwave-induced pre-gelatinization of corn flour and natural ones to produce gluten-free pan bread. To this end, the microstructure of pre-gelatinized corn flour was compared to the natural one. The result of the electron microscope image indicated the extension of structure and further swelling of the pre-gelatinized corn flour as compared to the natural one. In addition, the result represented that samples containing pre-gelatinized corn flour had a firmer dough, more moisture, porosity, specific volume, the L* component of the crust and crumb texture, the a* component of crumb texture and the sensory properties when compared to those which contained the native corn flour. Based on the results, pre-gelatinized corn flour caused a decrease in the b* component in the crust and crumb texture, along with firmness during 2 and 72 h after baking. On the other hand, the ultrasound waves resulted in a reduction in the dough and bread firmness and b* colorful component while those with 30% intensity increased the L* colorful component, specific volume, porosity, and the overall acceptability score in sensory assessment. In general, the sample containing pre-gelatinized corn flour, treated with 30% intensity of ultrasound waves demonstrated better technological, visual, and sensory properties and was considered as a superior sample in the present study.