Rheological properties for determining the interaction of soluble cress seed mucilage and β-lactoglobulin nanocomplexes under sucrose and lactose treatments

Pickering Emulsion Stabilized by Different Concentrations of Whey Protein-Cress Seed Gum Nanoparticles

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.

The non-covalent and covalent interactions of whey proteins and saccharides: influencing factor and utilization in food

During the application of Whey proteins (WPs), they often have complex interactions with saccharides (Ss), another important biopolymer in food substrate. The texture and sensory qualities of foods containing WPs and Ss are largely influenced by the interactions of WPs-Ss. Moreover, the combination of WPs and Ss is possible to produce many excellent functional properties including emulsifying properties and thermal stability. However, the interactions between WPs-Ss are complex and susceptible to some processing conditions. In addition, with different interaction ways, they can be applied in different fields. Therefore, the non-covalent interaction mechanisms between WPs-Ss are firstly summarized in detail, including electrostatic interaction, hydrogen bond, hydrophobic interaction, van der Waals force. Furthermore, the existence modes of WPs-Ss are introduced, including complex coacervates, soluble complexes, segregation, and co-solubility. The covalent interactions of WPs-Ss in food applications are often formed by Maillard reaction (dry or wet heat reaction) and occasionally through enzyme induction. Then, two common influencing factors, pH and temperature, on non-covalent/covalent bonds are introduced. Finally, the applications of WPs-Ss complexes and conjugations in improving WP stability, delivery system, and emulsification are described. This review can improve our understanding of the interactions between WPs-Ss and further promote their wider application.

Rheological Characteristics of Soluble Cress Seed Mucilage and β-Lactoglobulin Complexes with Salts Addition: Rheological Evidence of Structural Rearrangement

Functional, physicochemical, and rheological properties of protein-polysaccharide complexes are remarkably under the influence of the quality of solvent or cosolute in a food system. Here, a comprehensive description of the rheological properties and microstructural peculiarities of cress seed mucilage (CSM)-β-lactoglobulin (Blg) complexes are discussed in the presence of CaCl₂ (2-10 mM), (CSM-Blg-Ca), and NaCl (10-100 mM) (CSM-Blg-Na). Our results on steady-flow and oscillatory measurements indicated that shear thinning properties can be fitted well by the Herschel-Bulkley model and by the formation of highly interconnected gel structures in the complexes, respectively. Analyzing the rheological and structural features simultaneously led to an understanding that formations of extra junctions and the rearrangement of the particles in the CSM-Blg-Ca could enhance elasticity and viscosity, as compared with the effect of CSM-Blg complex without salts. NaCl reduced the viscosity and dynamic rheological properties and intrinsic viscosity through the salt screening effect and dissociation of structure. Moreover, the compatibility and homogeneity of complexes were approved by dynamic rheometry based on the Cole-Cole plot supported by intrinsic viscosity and molecular parameters such as stiffness. The results outlined the importance of rheological properties as criteria for investigations that determine the strength of interaction while facilitating the fabrication of new structures in salt-containing foods that incorporate protein-polysaccharide complexes.