The Amylograph profile of dry‐heated (120°C, 120 min) wheat flour showed a drastic change, i.e. an earlier onset time and higher peak viscosity than that of a control. However, no difference in the size of the starch granules was observed between dry‐heated and normal starch at every temperature. Wheat flour was fractionated with acetic acid, and the separated prime starch (PS) and tailings (T) fractions were dry‐heated at 120°C for 30, 60, 90, and 120 min, respectively. There was almost no difference in the RVA and DSC profiles between PS and dry‐heated PS, and T and dry‐heated T fractions, i.e., dry heating of wheat flour did not change the structures of starch that would be related to onset time and peak viscosity in the Amylograph profile. We thus excluded the water solubles (WS) fractions from control and dry‐heated wheat flour, but the effect of dry heating on the Amylograph profile was not lost. Next, the gluten (G) fraction was excluded following WS fraction from these wheat flours, and Amylograph tests were performed. The Amylograph profiles in both wheat flours were almost coincidental, which showed that the G fraction in dry‐heated wheat flour caused the earlier onset time and higher peak viscosity.

Dry heated wheat flours were fractionated into water-soluble, gluten, prime-starch and tailings fractions by an acetic acid fractionation technique. With a gradual increase in the duration time at each temperature, recovery of the prime-starch fraction decreased while the tailings fraction increased. However, the water-soluble and gluten fractions did not change, which is indicated by the fact that interaction between the prime-starch and the tailings fractions occurred for these treatments. A mixograph profile showed hydrophobicity of the wheat flour by dry heating. These dry heated wheat flours gave a large pancake springiness. The temperatures and the duration times for complete pancake springiness were as follows ; at 0*῍C for /.* h (,,./ days) ; 1*῍C

Cereal Chem. 81(5):633-636Dried egg white protein was heated at 120°C for 1 hr, added to a fresh wheat flour (protein 8.6%), and the protein and wheat flour were subjected to acetic acid (pH 3.5) fractionation. The results showed that egg white protein increased the binding between prime starch (PS) and tailings (T) fractions in wheat flour. Several conditions for heating of egg white protein were examined to determine 1) the effect of the amount of water added to the protein before heating; 2) the effect of heating time (hr) on protein at 120°C; and 3) the effect of heating temperature on the binding between PS and T fractions. The amount of protein per 50.0 g of wheat flour was further examined for the maximum binding between PS and T fractions. The heated egg white protein was analyzed by Fourier trans-form infrared (FT-IR) spectroscopy, and the changes in the secondary structures (α-helix, β-sheets, and others) of the protein caused by heating were studied. When egg white protein was heated at 120°C for 8 hr, 9.0% of the α-helix structures of egg white protein decreased to 3.0%, and 37.0% of the β-sheet structures increased to 41.0%. The decrease of αhelix and increase of β-sheet structures of heated egg white protein were related to the increase in the binding between PS and T fractions in the same heated egg white protein and wheat flour sample. A relationship between the structural changes in heated egg white protein (180°C, 1 hr) and the binding between PS and T fractions in the heated egg white protein and wheat flour was also observed.

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Gluten-free bread baked with yam flour (Jinennjyo; Dioscorea japonica), wheat starch, sugar (sucrose), compressed yeast, and water showed similar bread making properties, such as bread height (mm) and specific volume (cm 3 /g), to that of wheat bread. Yam flour was dialyzed against water and separated into nondialyzable (high-molecular-weight (HMW)) fraction and dialyzable (low-molecular-weight (LMW)) fractions. The fractions were dried and used separately in bread making in the same manner. The results indicated that the HMW or LMW fractions showed poor bread making properties when used individually, whereas bread baked with a mixture of the HMW and LMW fractions exhibited good bread making properties. Next, the LMW fraction was separated into peptide and sugar subfraction by paper chromatography. Addition of the peptide subfraction to the HMW fraction resulted in better bread making properties than addition of the sugar subfraction.