The impedance of the cubic perovskite BaZr 0.9 Y 0.1 O 3-␦ has been systematically investigated in dry and wet atmospheres at high and low oxygen partial pressures. In the grain interior, conductivity contributions from oxygen ions, electron holes, and protons can be identified. Below 300°C, proton conduction dominates and increases linearly with the frozen-in proton concentration. The proton mobility, with an activation energy of 0.44 ؎ 0.01 eV is among the highest ever reported for a perovskite-type oxide proton conductor. For dry oxygen atmospheres, electron hole conduction dominates with an activation energy of ϳ0.9 eV. At temperatures <500°C, the grainboundary conductivity can be separated and increases upon incorporation of protons. The high electrical conductivity and chemical stability make acceptor-doped barium zirconate a good choice for application as a high-temperature proton conductor.

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Cereal Chem. 82(4):394-404 Gluten-free breadmaking quality of 10 sorghum flours was compared using (relative basis) decorticated sorghum flour (70), corn starch (30), water (105), salt (1.75), sugar (1), and dried yeast (2). Batter consistency was standardized by varying water levels to achieve the same force during extrusion. Crumb properties were evaluated by digital image analysis and texture profile analysis (TPA). Significant differences (P < 0.001) in crumb grain were found among the hybrids with mean cell area ranging from 1.3 to 3.3 mm 2 and total number of cells ranging from 13.5 to 27.8/cm 2. TPA hardness values of the crumb also varied significantly (P < 0.001). Based on significant correlations (P < 0.01), starch damage, influenced by kernel hardness, was identified as a key element for these differences. Breads differed little in volume, height, bake loss, and water activity. Investigation of added ingredients on bread quality was conducted using response surface methodology (RSM) with two sorghum hybrids of opposite quality. Addition of xanthan gum (0.3-1.2% flour weight basis [fwb]) and skim milk powder (1.2-4.8% fwb) and varying water levels (100-115% fwb) were tested using a central composite design. Increasing water levels increased loaf specific volume, while increasing xanthan gum levels decreased the volume. As skim milk powder levels increased, loaf height decreased. Quality differences between the hybrids were maintained throughout the RSM.

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