Abstract: The specific volume and texture properties of steamed bread and the secondary structure of gluten were determined by a volume meter, a texture analyzer and Fourier transform infrared (FTIR) spectroscopy, respectively. The effects of fermentation time on bread quality and gluten protein structure were investigated. The results showed that β-sheet was the dominant secondary structure for both the glutenin and gliadin in steamed bread. The contents of β-sheet and α-helix in the gliadin did not significantly change with fermentation time, whereas random coil gradually decreased and β-turn increased; the intensity of the hydroxyl absorption band was gradually increased, and the hydration of the gliadin was enhanced. For the glutenin, the contents of α-helix and random coil changed little; β-sheet content increased first and then decreased while the opposite was observed for β-turn. The intensity of the hydroxyl absorption band gradually declined. The peaks at 1 082 cm-1 and 1 155 cm-1 in the FTIR spectrum of the glutenin disappeared at 80 min of fermentation, which may be attributed to the weakened C–C vibration of the protein ring structure

Key words: gluten, Fourier transform infrared spectroscopy, fermentation, steamed bread