Structure, rheology, and functionality of emulsion-filled gels: Effect of various oil body concentrations and interfacial compositions

The purpose of this study is to investigate the impact of varied oil body (OB) concentrations and interfacial compositions on the network topology and rheological and functional aspects of composite whey protein isolate (WPI) gels. Particle size and ζ-potential analyzes of the mixed gel solutions containing the OBs extracted at pH 6.8 (6.8-OB) and 11.0 (11.0-OB) revealed a greater aggregation in the 6.8-OB-containing mixed gel solution. 6.8-OB and 11.0-OB generated particle aggregates and oil-drop-embedded network architectures in the WPI gel, respectively. FT-IR analyses showed that OBs stabilized the protein gels' polymeric matrix by hydrogen bonding, steric hindrance, and hydrophobic interactions. Rheology and texture showed that OBs hardened gels. Low-field nuclear magnetic resonance showed that excessive inclusion of OBs (30% of 6.8-OB and 35% of 11.0-OB) compromised gel integrity and freeze–thaw stability. This study found that OBs can be active fillers in protein gels for functional meals.