Interfacial rheology of sodium caseinate/high acyl gellan gum complexes: Stabilizing oil-in-water emulsions

Abstract

In this work, the effects of pH and high acyl gellan gum concentration on the adsorption kinetics and interfacial dilatational rheology of sodium caseinate/high acyl gellan gum (CN/HG) complexes were investigated using a pendant drop tensiometer. In addition, stability related properties including interfacial protein concentration, droplet charge, size, microstructure and creaming index of emulsions were studied at different HG concentration (0–0.2 wt%) and pH values (4, 5.5 and 7). The results showed that HG adsorbed onto the CN mainly through electrostatic interactions which could lead to increase the interfacial pressure (π), rates of protein diffusion (k diff ), and molecular penetration (k p ). The CN/HG complexes formed thick adsorption layers around the oil droplets which significantly increased the surface dilatational modulus with the increasing HG concentration. The CN/HG complexes appeared to form more elastic interfacial films after a long-term adsorption time compared with CN alone, which could reduce the droplet coalescence and thus prevented the growth of emulsion droplets. All four phosphorylated proteins of CN (α s1 -, α s2 -, β-, and κ-casein) were adsorbed at the oil-water (O/W) interface as confirmed by sodium dodecyl sulphate polyacrylamide gel electrophoresis (SDS-PAGE), and surface protein coverage increased progressively with increasing HG concentration at pH 5.5, but decreased at pH 7. The CN/HG stabilized emulsions at pH 5.5 revealed the higher net charges and smaller z-average diameters than those at pH 4 and pH 7. This study provides valuable information on the use of CN/HG complexes to improve the stability and texture of food emulsions.

Interfacial Behavior and Long-Term Stability of the Emulsions Stabilized by Sugar Beet Pectin–Ca2+ Complexes with Different Cross-Linking Degrees

“…To study the change of the viscoelastic modulus of these SBP-Ca 2+ complex-loaded interfacial films during their formation processes, time sweep was applied for 3 h at the conditions of 5% amplitude (Δ A / A ) and 0.05 Hz frequency. Droplet volume was 30 μL, and temperature was 25 °C. , σ = σ 0 0.25em sin ( ω t + φ ) A = A 0 0.25em sin ( ω t ) E = normald σ / ( d A / A ) = prefix− normald π / normald 0.25em ln nobreak0em0.25em⁡ A E = ( σ 0 / A 0 ) ( cos ⁡ φ + i ⁡ sin ⁡ φ ) = E d + iE v tan nobreak0em0.25em⁡ φ = E v / E d E d = | E | cos nobreak0em0.25em⁡ φ E v = …”

“…To study the change of the viscoelastic modulus of these SBP-Ca 2+ complex-loaded interfacial films during their formation processes, time sweep was applied for 3 h at the conditions of 5% amplitude (Δ A / A ) and 0.05 Hz frequency. Droplet volume was 30 μL, and temperature was 25 °C. , where σ and σ 0 refer to the dilatational interfacial tensions of the adsorption process at random t time and the initial time (0 s), respectively. Similarly, A and A 0 refer to the surface areas of the drop during the oscillation process at random time and the initial time (0 s), respectively.…”

Wheat gluten proteins phosphorylated with sodium tripolyphosphate: Changes in structure to improve functional properties for expanding applications

“…The distribution of particle size for WG and PP-WG samples was determined using a laser particle size instrument of Mastersizer-2000 (Malvern Ltd, UK) basing on previous reference ( Farooq et al, 2022 ). After the instrument was calibrated with blue light, samples were added when the light transmission was 75% or more, and measurements started when the sample shading was 8%.…”

Improving emulsification properties of alkaline protein extract from green tea residue by enzymatic methods

“…In addition, the conditions of enzyme hydrolysis can be controlled to further improve protein emulsification properties. Proteins can be partially degraded, thereby improving the emulsification properties of protein products due to the exposure of more hydrophilic or hydrophobic groups ( Jung et al, 2010 ; Farooq et al, 2022 ).…”