Bigels as emerging biphasic systems: Properties, applications, and prospects in the food industry

Bigels, as emerging biphasic systems, have garnered significant attention owing to their advantages encompassing both hydrogels and oleogels. The performance and application of bigels in food systems depend strongly on their mechanical properties. Therefore, acquiring a rational understanding of bigels with varied mechanical properties for distinct application scenarios is crucial for expanding their practical applications. This review emphasizes the intrinsic characteristics and extrinsic factors influencing the mechanical properties of bigels. This insight enables the design of the mechanical properties of bigels for specific food-related applications, with a particular focus on their use as nutrient delivery systems, fat replacers, food packaging, and 3D printing food. The mechanical properties of bigels depend on intrinsic characteristics, such as the ratio between oleogel and hydrogel, and types of organogelators/hydrogelators, as well as extrinsic factors, including the incorporation of additives/emulsifiers and pH. The changes in intrinsic characteristics could alter the interfacial area, structural arrangement, and degree of crosslinking and the polymer strength of phases. Moreover, extrinsic factors play crucial roles in modifying the mechanical properties of bigels by influencing the interactions between the oleogel and hydrogel and enhancing the interfacial and structural stabilization of bigels. Understanding these factors allows for more precise design of bigels characteristics, thereby enhancing their suitability in various food industries.