1e:T4a3,Particle-stabilized W₁/O/W₂ emulsion gels were fabricated using a two-step procedure: ( i) a W₁/O emulsion was formed containing saccharose (for osmotic stress balance) and gelatin (as a gelling agent) in the aqueous phase and polyglycerol polyricinoleate (a lipophilic surfactant) in the oil phase; ( ii) this W₁/O emulsion was then homogenized with another water phase (W₂) containing wheat gliadin nanoparticles (hydrophilic emulsifier). The gliadin nanoparticles in the external aqueous phase aggregated at pH 5.5, which led to the formation of particle-stabilized W₁/O/W₂ emulsion gels with good stability to phase separation. These emulsion gels were then used to coencapsulate a hydrophilic bioactive (epigallocatechin-3-gallate, EGCG) in the internal aqueous phase (encapsulation efficiency = 65.5%) and a hydrophobic bioactive (quercetin) in the oil phase (encapsulation efficiency = 97.2%). The emulsion gels improved EGCG chemical stability and quercetin solubility under simulated gastrointestinal conditions, which led to a 2- and 4-fold increase in their effective bioaccessibility, respectively.1f:T522,beta-Lactoglobulin and whey protein isolate (WPI) were heated in aqueous solutions at pH 2 and 7 at 80 degrees C, spread onto freshly cleaved mica surfaces, and visualized under butanol using atomic force microscopy. Fine-stranded aggregates were formed at pH 2, the diameter of strands being ca. 4 nm for beta-lactoglobulin and 10 nm for WPI. At pH 7, aggregates were composed of ellipsoidal particles, regardless of the concentration of added NaCl. This observation supports the previously proposed two-step aggregation model at neutral pH (Aymard, P.; Gimel, J. C.; Nicolai, T.; Durand, D. J. Chim. Phys. 1996, 93, 987-997), consisting of the formation of primary globular particles and the subsequent aggregation of those primary particles. The AFM provides the first direct evidence for the anisotropic shape of these primary particles. The heights of primary particles increased from ca. 11 to 27 nm with increasing concentrations of added NaCl from 0 to 0.3 M in the case of WPI. The rate of aggregation was also accelerated with increasing NaCl concentrations, which appeared to induce transitions in gel networks from fine-stranded toward particulate networks. The present study provides structural information essential for understanding the diverse physical properties of heat-induced whey protein gels.

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