Functional properties and structural characteristics of phosphorylated pea protein isolate

In order to expand the application of pea proteins in the food industry, pea protein isolate (PPI) was chemically phosphorylated to improve its functional properties. Based on the comprehensive membership value (CMV) degree, the optimal condition for PPI phosphorylation modification was as follows: pH 12, modification temperature at 70 degrees C and an addition of 7.0% (w/v) sodium tripolyphosphate (STP). Under this condition, the solubility, emulsifying property, emulsifying stability, foaming property and oil absorption capacity of the modified PPI were improved substantially. In addition, the structure of modified PPI was characterised by scanning electron microscope (SEM) and Fourier transform infrared (FTIR) spectroscopy. The results showed that the modified PPI had a smooth and uniform lamellar structure, where the content of alpha-helix and beta-sheet structure increased, but the content of beta-corner and random coil structure decreased. The thermodynamic properties were analysed by differential scanning calorimetry (DSC) and the results showed that increment H of the modified PPI increased significantly. Finally, the optimum phosphorylated PPI was mixed with 0.4% (w/v) xanthan gum to form PPI fat mimics (PPI-FM). PPI-FM was added into mango mousse cake to reduce the amount of light cream, and the result showed up to 20% of light cream could be substituted.