Structural characterization of oleogels from whey protein aerogel particles

[Display omitted] •Whey protein aerogel particles show oleogelation ability.•Hydrogel drying technique affects aerogel and oleogel structure.•Oil structuring is controlled by surface absorption and particle-particle interactions.•Aerogel particles form a network in oil thanks to hydrophilic interactions.•Oleogels from supercritical-dried particles show rheological features of common fats. Oleogels intended as fat substitutes were prepared by oil dispersion of aerogel particles obtained through freeze-drying (FD) or supercritical-CO2-drying (SCD) of whey protein isolate (WPI) hydrogels (20 g/100 g). SEM revealed that freeze-dried particles presented larger dimensions than supercritical-dried ones. The latter also showed higher oil dispersibility, forming aggregates with lower dimension (300 nm) than those formed by freeze-dried particles (700 nm). Both particles presented oil structuring capability. Freeze-dried particles gave a weak oleogel, while supercritical-dried ones gave a strong (G′ = 3.1 × 105 Pa) and plastic (critical stress = 723.2 Pa) oleogel, with rheological features comparable to those of traditional fats. These results can be explained based on the lower aggregation induced by SCD and on the higher capacity of supercritical-dried particles to form a network in oil through hydrophilic interactions, as suggested by FTIR. Therefore, WPI aerogel particles show the potentiality to be used as food ingredients to prepare oleogels with tailor-made physical properties.