Sorghum Flour Characterization and Evaluation in Gluten-free Flour Tortilla

Four sorghum hybrids (Fontanelle-625 [F-625]), Fontanelle-1000 [F-1,000], ATx631xRTx2907 [NE#20] and 5,040C) were characterized and evaluated for kernel characteristics, proximate analysis, flour characterization (particle size distributions, starch damage, amylose content and starch pasting properties) and end product in gluten-free tortilla. A commercial sorghum flour (TVM) was used as a control. Significant differences were found (P < 0.05) among hybrids for kernel and flour composition except total starch (P > 0.05). NE#20 had the largest particle diameter for both flour and starch. F-1000 had significantly higher starch damage compared with the other hybrids. Flours with smaller particle size and higher starch damage contributed to softer and more extensible tortilla. Amylose content ranged from 20.2 (NE#20) to 27.3 (F-1000). Tortilla made with TVM flour had the highest extensibility, while the F-625 tortilla had the lowest. F-625 tortilla had the lightest color with L* value of 70.38, while the 5,040C tortilla had the darkest with L* value of 61.68. Descriptive sensory results showed significant differences for tortilla grain specks, angle of bend, rancidity, sweetness, springiness, hardness and grittiness. The results have shown that sorghum hybrids can differ in kernel and flour properties, which could help predict sorghum flour quality for the purpose of gluten-free products.