Measurements were conducted at a scattering angle of 173°a nd at 22.0 ± 1 °C. The particle had a z-average of 77.0 ± 12.8 nm and a polydispersity index of 2.64 ± 0.59.
The zeta-potential of MGP suspensions containing 1 wt% MGPs was determined using the particle size analyser Horiba Nanopartica SZ-100 (Horiba Scientific, Kyoto, Japan), at pHvalues 4, 3, and 2 without adjusting the electric conductivity (EC) of the water phase. Additionally, the EC MGP suspensions at pH 4 were adjusted to 0.65 mS cm -1 and 6.5 mS cm -1 with a saturated NaCl solution prior to the zeta-potential measurements. The zeta-potential of MGP suspensions at pH 3 and EC 6.5 mS cm -1 was also determined. Three measurements of 10 runs were conducted at 25 °C for each solution.