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Journal of Chemistry
Volume 2014, Article ID 475389, 10 pages
Research Article

Relationship between Secondary Structure and Surface Hydrophobicity of Soybean Protein Isolate Subjected to Heat Treatment

College of Food Science, Northeast Agricultural University, Harbin, Heilongjiang 150030, China

Received 22 October 2013; Revised 6 April 2014; Accepted 14 April 2014; Published 8 May 2014

Academic Editor: Blanca Hernández-Ledesma

Copyright © 2014 Zhongjiang Wang et al. This is an open access article distributed under the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original work is properly cited.


This study investigated relationship between secondary structure and surface hydrophobicity of soy protein isolate (SPI) subjected to a thermal treatment at 70~90°C. Heat denaturation increased the surface hydrophobicity and surface hydrophobicity decreased as aggregate formed. Heat caused an increase in the relative amount of α-helix structures and an overall decrease in the amount of β-sheet structures when compared with nontreated SPI. The relative amounts of secondary structures varied with time, temperature, and intensity of heat treatment applied. The β-sheet structure was most important for its significant role in denaturation of 7S globulin and following formed aggregates and even in denaturation of 11S globulin. The amount of β-sheet structure in SPI had an inverse correlation with the surface hydrophobicity when the temperature was kept below 90°C. Besides, β-turn structure increased as β-7S/B-11S aggregate formated.