Ph.D. Dissertation:

Application of new technologies (ultrasound and microwave) and Balangu Shirazi (Lallemantiaroyleana) gum in the production of gluten-free bread based on corn flour

The aim of this study was to produce gluten-free bread based on natural corn flour and microwave heat-treated corn flour, with Balangu Shirazi (Lallemantia Royleana) gum (0, 1 and 2%), and ultrasound intensity (0, 30 and 70%). The physicochemical characteristics of both types of flour were investigated and revealed that both corn flours were not significantly different, but the images of the electron microscope indicated that the structure of the microwave heat-treated corn flour granules had a higher structural expansion and swelling. The results showed that the dough contained microwave heat-treated corn flour, 1% Balangu Shirazi gum, and the ultrasonic treatment with 30% and 70% intensity had the least firmness. In addition to dough, examination of electron microscope images of made breads and their sensory testing, the superiority of the sample containing microwave heat-treated corn flour, 1% Balangu Shirazi gum, and 30% ultrasound intensity exposure. By increasing the amount of gum and applying higher ultrasound intensity in microwave heat-treated corn flour samples, the moisture and water activity parameters in the breads showed an up trend. In terms of technological characteristics, the results indicated that the sample contained microwave heat-treated corn flour, 1% Balangu Shirazi gum, and ultrasonication with 30% intensity of the highest specific volume and porosity and the minimal texture firmness at both time intervals 2 and 72hrs after heating. The results of color components of gluten-free pan bread showed that the use of microwave heat-treated corn flour, increasing the level of Balangu Shirazi gum absorption and ultrasonication increased the colorful component of the L* crust and the internal texture of the bread. The lack of effect of the three factors on corn flour, the level of gun consumption, and the intensity of ultrasound on the colorful component of a* crust were determined, while only the main factors that only the microwave heat-treated corn flour had a significant effect on the components of the internal texture of the bread, and reduced it. Also, microwave heat-treated corn flour and ultrasonic application reduced the colorful component of b* crust and internal texture.

Keywords: Corn flour, Ultrasonic waves, Balangu Shirazi (Lallemantia Royleana) gum, Microwave, Gluten-free bre