Correlation between Molecular Flexibility and Emulsifying Properties of
Soy Protein Isolate-Glucose Conjugates Based on pH Treatment
Abstract
The research on the structure-function relationship between the
molecular flexibility and emulsifying properties of soybean protein
isolate (SPI) under Maillard reaction conditions is still very limited
until now. This paper investigated the effects of different pH values
(5.0, 6.0, 7.0, 8.0, 9.0) on the molecular flexibility, emulsifying
activity and emulsion stability of Maillard reaction products between
soybean protein isolate with glucose. As the pH increased, the degree of
grafting and browning of soybean protein isolate-glucose (SPI-G)
increased significantly. The results of secondary structure analysis
showed that the α-helix content decreased, which further proved that the
protein flexibility increased. Correlation analysis showed that there
was a good correlation between molecular flexibility and emulsifying
properties of SPI-G. The correlation coefficient between the molecular
flexibility and emulsifying activity of SPI-G was 0.963 (P
<0.01), and the correlation coefficient between the molecular
flexibility and emulsion stability of SPI-G was 0.879 (P
<0.05).