Improving the emulsifying property of gliadin nanoparticles as stabilizer of Pickering emulsions: Modification with sodium carboxymethyl cellulose

In the present work, sodium carboxymethyl cellulose (CMCNa) was utilized to improve the emulsifying property of gliadin colloid particles (GCPs). We demonstrated the use of gliadin/CMCNa complex particles (GCCPs) as stabilizer to stabilize oil-in-water emulsions in a wide pH range (3.0-9.0) at a very low protein concentration (0.1%, w/v) which could be kept at room temperature for three months without oil-leakage. The effect of gliadin/CMCNa ratio, pH and ionic strength on emulsifying property of gliadin-based particles was investigated, and the stability of Pickering emulsions fabricated by GCCPs at a series of pH (3.0-9.0) to a four-week-long storage was evaluated. The optimized emulsifying property of particles was achieved at a gliadin/CMCNa ratio of 2:1, and Pickering emulsions stabilized by GCCPs at this ratio had a high tolerance for aqueous phase pH variation. Furthermore, the possible mechanisms were discussed by investigating the effect of gliadin/CMCNa ratio on wettability and adsorption behavior of particles at pH 4.0 and pH 7.0. Moderate wettability was achieved at the gliadin/CMCNa ratio of 1:1 at pH 4.0 and 2:1 at pH 7.0. The surface loading percentage of protein of Pickering emulsions increased from 70.28 +/- 1.97% to 82.02 +/- 6.20% and the surface protein loading (tau) decreased from 267.53 +/- 5.31 mg/m(2) to 149.17 +/- 4.45 mg/m(2) with the increase of CMCNa concentration, indicating the adsorption and emulsifying activity of particles could be enhanced by CMCNa addition.