Cereal Chem. 75(1):58-63Tempering agents affect the pericarp of steamed grain and the endosperm of steam-flaked sorghum. Examination by environmental scanning electron microscopy (ESEM) clearly showed that β−mercaptoethanol (BME), sulfurous acid (SA), phosphoric acid, and cellulase significantly altered the structure of the pericarp and endosperm during tempering. Lime and protease had a lesser effect on the pericarp structure of the kernels, and had little effect on the endosperm. Steamed flakes from the SA treatment were more translucent and durable than all other treatments. Flakes with BME were translucent and high in quality, but were more fragile than the SA flakes. Nontempered, water only, and commercial conditioner treatments produced flakes with the lowest quality. Peak, final, and breakdown Rapid Visco Analyzer (RVA) viscosities were low-est for the SA flakes due to disruption of the starch chains by the weak acid. BME viscosity values were higher than SA, but lower than the water and commercial tempering treatments. The commercial conditioner (15× normal concentration) did not alter kernel structure and did not cause any changes in the RVA profiles over kernels tempered with water alone. Starch gelatinization, measured by enzyme susceptible starch (ESS), was highest in the SA and BME flakes and lowest in the nontempered flakes. Feedlot operators may be able to save money by avoiding the use of chemical additives that do nothing to the grain. By using chemicals proven to have positive effects on flake quality, operators could save money by reducing the processing time and energy needed to produce good quality flakes.

Commercial and food‐type sorghum hybrids with differing kernel and endosperm characteristics were grown under comparable conditions and steam flaked in each of three years. The raw‐grain kernel characteristics and proximate analyses were homogenous over the three‐year period. The waxy hybrid produced large, translucent, durable flakes that had significantly higher enzyme‐susceptible starch values for all years compared to the other varieties. Flakes with lower amylose contents (waxy endosperm) were positively correlated with percent whole flakes (r2 = 0.509), flake diameter (r2 = 0.846), and enzyme‐susceptible starches (r2 = 0.564) and negatively correlated with higher flake fragility (r2 = ‐0.647), test weight (r2 = ‐0.626), and flake breakage (r2 = ‐0.560). The heterowaxy flakes had a good appearance and were generally comparable in quality to the nonwaxy commercial and experimental hybrids. Heterowaxy sorghum hybrids with good grain yields can provide improved quality grain and flakes without sacrificing agronomic performance and yields. No difference in flaking performance was detectable among the kernels with different pericarp colors; flakes from the white food‐type sorghums had excellent appearance. Nontempered control samples were inferior in quality to all conditioned treatments.