Relationship between Rheological Properties and Conformational States of 7S Globulin from Soybeans at Acidic pH
We propose a simple method for isolating 7S and 11S globulins in high purity, and study the effects of pH on the rheological properties of the obtained 7S gel. Using this method, the heating differential scanning calorimetry (DSC) curve of each fraction shows only one endothermic peak. The storage modulus G’ of 7S globulin gel rapidly increased with decreasing pH below 5.5 – 6. Fourier transform infrared (FT-IR) measurements suggested that as pH fell below 5.5 – 6, 7S globulin tended to denature with heat, and the number of exposed β -strands increased. Thus, the number of intermolecular bonds which were available for the formation of gel networks increased, and a rigid gel formed at acidic pH.
KeywordsRheological Property Endothermic Peak Storage Modulus Soybean Protein Seed Storage Protein
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