Composition, in vitro digestibility, and sensory evaluation of extruded whole grain sorghum breakfast cereals

Two sorghum genotypes (red, tannin; white, non-tannin), were evaluated for their potential use in breakfast cereals. Two levels of whole grain sorghum flour (550g/kg dry mix or 700g/kg dry mix) were processed per genotype using a pilot-scale, twin screw extruder. A whole grain oat-based cereal was used as a reference. White sorghum cereals (WSC) had significantly (p<0.05) higher starch, brightness (L*), and yellowness (b*) than red sorghum cereals (RSC). RSC had higher protein and bulk density than the WSC. Cereals made with 700g sorghum flour/kg were smaller and denser with lower water solubility and absorption indices than those made with 550g/kg. Invitro protein digestibility of the RSC (43-58%) was significantly reduced compared with the WSC (69-73%) and the reference sample (72%). WSC with 700g sorghum flour/kg contained significantly more resistant starch than the RSC cereals and the oat reference (208g/kg starch versus 81-147g/kg starch, respectively). Overall acceptability and texture of sorghum cereals did not differ significantly from the oat reference, although appearance and aroma liking were significantly reduced. Therefore, non-tannin sorghum has potential to be used in the breakfast cereal industry with minimal impact on nutritional profile and sensory properties.