Structural Variations in the Subunits of Peanut Protein Isolates under Acidic Conditions
Article
Figures
Metrics
Preview PDF
Reference
Related
Cited by
Materials
Abstract:
Structural variations in the subunits of peanut protein isolates under acidic conditions were investigated using sodium dodecyl sulfate-polyacrylamide gel electrophoresis (SDS-PAGE), zeta potential, solubility, endogenous fluorescence spectroscopy, and particle size distribution analyses. The electrophoresis analysis indicated that when the pH value was <3.5, a portion of the subunits unfolded, a new 33 ku band was produced, and the intensity of the 18 ku band increased. The acid-hydrolysis of the subunits was affected by time and ionic strength. The peanut protein isolate subunits were subjected to acid-hydrolysis at pH 2.5 after 10 min at room temperature, and the amount of high molecular weight subunits decreased over time. When the ionic strength ranged from 0~0.1 mmol/L, there was a higher degree of acid-hydrolysis, which was inhibited when the ionic strength was above 0.2 mmol/L. Moreover, at pH values ranging from 2.0~2.5, the peanut protein isolate unfolded, interior groups were exposed, solubility was relatively high, and the maximum emission wavelength in the fluorescence spectra was red-shifted by 13.47 nm as compared to that under neutral conditions. When the pH was further decreased, the zeta potential was relatively low, peanut protein isolates formed high molecular weight soluble aggregates, and the maximum emission wavelength in the fluorescence spectra was blue-shifted to 335.27 nm.
