Biopolymer-based capillary oleogels: From interfacial regulation to structure-function relationships and food applications.

The development of healthy fat alternatives with desirable sensory properties is essential to reduce the health risks associated with excessive intake of saturated and trans fatty acids. Although oleogel technology enables the structuring of liquid oils into solid-like systems, conventional oleogelators often require harsh processing conditions, chemical modification, or complex fabrication routes. Capillary suspension has emerged as a promising physical strategy, where a small amount of secondary fluid induces capillary bridges between particles to construct a three-dimensional network for oil immobilization. This approach enables the direct fabrication of oleogels using natural unmodified biopolymer particles under mild conditions, supporting clean-label and sustainable processing. This review summarizes the principles of capillary suspension, including interfacial design, structural regulation, and structure-function relationships, and discusses its potential applications in food and related materials. Capillary suspension provides a green strategy for developing next-generation healthy fat substitutes.