Structural and flow behavior of pickering emulsions stabilized by WPI–gum arabic complexes under simulated digestion

Date

2026-01-01

Author

Kaya, Esranur
İlhan, Esmanur
Akgoz, Elif Doga
Guneydere, Gulfem
Gurbuz, Imran
Öztop, Halil Mecit

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Pickering emulsions stabilized by acid-gelling particles offer potential for functional foods, nutraceuticals, and controlled nutrient release. This study investigated emulsions prepared with whey protein isolate (WPI) and gum Arabic (GA) at varying ratios (0.01–0.10) to assess their ability to undergo intragastric gelation. Polysaccharide–protein complexes were formed under heat and pressure at neutral pH, likely through hydrogen bonding, hydrophobic interactions, and steric effects. GA–WPI complexation at neutral pH was investigated using FTIR spectroscopy and NMR relaxometry and further analyzed by zeta potential. Emulsions containing 20% w/w sunflower oil were produced using high-pressure homogenization, and their stability was tracked via particle size analysis and NMR relaxometry over four weeks. Confocal microscopy revealed the formation of a GA–protein coating around oil droplets, indicating strong interfacial stabilization. Increasing GA concentration from 0.01 to 0.10 significantly reduced particle size (p ' 0.05), with the smallest recorded diameter being 0.756 µm. NMR relaxometry results demonstrated that higher PS:PR ratios led to lower T2a and T2b relaxation times, indicating increased particle-mediated confinement of the water and oil phases over four weeks and improved emulsion stability. During in vitro acid and enzyme-assisted digestion, emulsions demonstrated intragastric gelation. Rheological analysis showed increased bolus viscosity post-digestion, indicating network formation. Flow-MRI analysis of bolus flow revealed a shift from parabolic to flattened or asymmetric velocity profiles after digestion, influenced by GA ratio. These findings demonstrate that GA–WPI-based Pickering emulsions can undergo structural transformation during digestion, supporting their potential in developing functional food systems.

Subject Keywords

Flow-MRI, Gum Arabic, Intragastric gelation, Pickering emulsion, Rheology, Whey protein isolate

URI

https://www.scopus.com/inward/record.uri?partnerID=HzOxMe3b&scp=105032156058&origin=inward
https://hdl.handle.net/11511/118887

Collections

Department of Food Engineering, Article