Whey protein cryogel particles enable tunable design of multiphase systems: from oleogels to structured emulsions

This study aimed to understand the behavior of whey protein (WP) cryogel particles engaged in oil structuring in the presence of water. To this aim, an oleogel composed of sunflower oil, structured by WP cryogel particles (37 %, w/w), was progressively added with water, leading to systems containing 0–45 % (w/w) water. As control, native unstructured WP was also considered. Cryogel-based systems demonstrated high physical stability (liquid-holding capacity: 75–99 %), with diverse appearance and rheology depending on the water content. The system at 20 % (w/w) water showed a crumbly appearance and a brittle structure. By increasing water content at 30 %, a homogeneous gel-like solid was obtained, with lower elastic properties and higher tolerance to large deformations as compared to the starting oleogel. A further increase in water content (35–40 %) enhanced phase inversion, converting the oleogel into a structured oil-in-water emulsion with creamy appearance and significantly lower G’ and firmness as compared to the starting oleogel. When water content was increased to 45 %, a free-flowing oil-in-water emulsion with remarkable stability against phase separation (∼99 %) was obtained. Confocal microscopy was used to demonstrate the relationship between macrostructure and microstructure changes upon water addition. Results demonstrate the suitability of WP cryogel particles as a multipurpose ingredient in food structuring.