Fabrication and characterization of novel whey protein-based bigels as structured materials with high-mechanical properties

The focus of the present research was to produce new bigels as a semi-solid base matrix (gel or cream) with great potential in the food industry. Bigels were fabricated by the mixture of oleogels based on whey protein isolate (WPI)-aggregates and WPI-hydrogels in different ratios. Our results from the confocal microscopic observations showed that oleogel was dispersed throughout the entire network with the protein backbone and side chains in any of these structures; also a strongly punctuated fluorescence (pseudo-colored red) in the system revealed that the created bigels were categorized as oleogel-in-hydrogel type. Obviously, the hardness and viscoelastic moduli of bigels increased with a higher proportion of oleogels. Based on the 3D structure integrity of bigels, solid-like characteristics were observed (indicating the storage modulus was higher than the loss modulus). Moreover, temperature ramp analysis revealed that the thermal stability of the bigels directly was dependent on oleogel fraction.