Pickering Emulsion Stabilized by Different Concentrations of Whey Protein–Cress Seed Gum Nanoparticles
Maryam Davtalab, Sara Naji‐Tabasi, Mostafa Shahidi Noghabi, Artur J. Martins, Ana I. Bourbon, Miguel A. Cerqueira
Abstract
Nanoparticles based on food-grade materials are promising materials to develop Pickering emulsions for food applications. Initially, this study focuses on the development of nanoparticles through the utilization of a soluble complex of whey protein concentrate (WPC) and cress seed gum (CSG), which were modified by calcium chloride (CaCl2) as a cross-linker. The response surface methodology was used to investigate the impact of different concentrations of WPC (1–4% w/v), CSG (0–1% w/v), and CaCl2 (1–3 mM) on particle size, polydispersity index (PDI), and Zeta potential. The optimum conditions for the production of CSG–WPC nanoparticles (WPC–CSG NPs) were 0.31% (w/v) CSG, 1.75% (w/v) WPC, and 1.69 mM CaCl2, resulting in nanoparticles with average size of 236 nm and Zeta potential of −22 mV. Subsequently, oil-in-water (O/W) Pickering emulsions were produced with different concentrations of WPC–CSG NPs in optimum conditions. The contact angles of the WPC–CSG NPs were 41.44° and 61.13° at concentrations of 0.5% and 1%, respectively, showing that NPs are suitable for stabilizing O/W Pickering emulsions. Pickering emulsion viscosity rose from 80 to 500 mPa when nanoparticle concentration increased from 0.5% to 1%. Results also showed that WPC–CSG NPs enable stable O/W Pickering emulsions during storage and thermal treatment, confirming that protein–polysaccharide NPs can provide a sufficient steric hindrance.