Abstract: The effect of heat treatment on the surface hydrophobicity (H0) of 11S glycinin was researched and its secondary structure was analyzed by Raman spectroscopy before and after heat treatment. As the heat treatment time increased (80 ℃), H0 was increased and α-helix was transformed to β-turn and random coil structures. At both 90 and 100 ℃, H0 increased first and then decreased, while it changed faster and more significantly at 100 ℃, and α-helix and β-sheet were transformed to β-turn and random coil structures. Moreover, the tyrosine and tryptophan residues in the protein molecule were exposed after heat treatment. At the same time, the vibration mode of intermolecular disulfide bond in 11S glycinin was changed, transforming the disulfide bond from g-g-g configuration to t-g-t configuration, which may lead to an increase in protein surface hydrophobicity.

Key words: heat treatment, 11S glycinin, surface hydrophobicity, Raman spectroscopy