Preparation, characterization and stability of pea protein isolate and propylene glycol alginate soluble complexes

The application of pea protein in food products was ordinarily restricted to its poor acidic solubility and thermal stability. Propylene glycol alginate was first used to form soluble complexes with pea protein for solving these problems. In this study, the interaction between pea protein isolate (PPI) and PGA was investigated. Effects of PPI and PGA mass ratio (1:1–5:1) and pH (2–8) on the phase behavior of PPI-PGA soluble complexes were evaluated using phase diagram and zeta potential measurement. Results showed that the optimum mass ratio and pH value of the PPI-PGA binary soluble complex formed by electrostatic attraction were 3:1 and 4.0, respectively. The PPI-PGA binary soluble complex also enhanced stable and functional properties compared with native PPI. The protein solubility, emulsifying activity index and denaturation temperature were increased from 8.95 ± 1.69, 9.69 ± 0.02 and 76.69 ± 0.18 to 74.18 ± 0.81%, 82.84 ± 0.06 m2/g and 86.52 ± 2.38︒C, respectively. These improvements in the protein functionality and stability are of great practical significance to the application of pea protein in food products.