Advances in the preparation of food microgels and their application in functional foods

Food-grade microgels are micron- or submicron-scale soft particles formed by natural biomacromolecules through physical or chemical crosslinking. Due to their unique tunable three-dimensional network structure, excellent biocompatibility, and environmental responsiveness, they exhibit significant potential for application in functional Foods This review systematically elucidates the structure–function relationships of food microgels to guide their practical applications, focusing on the gelation mechanisms and structural characteristics of polysaccharide-based (e.g., starch, alginate, chitosan) and protein-based (e.g., soy protein, gelatin, whey protein) as well as composite food microgels. Based on this foundation, the principles, features, and applicability of top-down (e.g., mechanical fragmentation) and bottom-up (e.g., emulsification, microfluidics, molecular self-assembly) preparation techniques are analyzed in detail. Furthermore, recent advances in the applications of food microgels are reviewed comprehensively, including the delivery of functional factors (e.g., unsaturated fatty acids, lutein, vitamins, anthocyanins), stability protection, texture modification of foods (e.g., fat replacement, foods for dysphagia), and the construction of emulsification systems. Finally, this review discusses key challenges currently hindering the translation from microscopic mechanisms to macroscopic applications—such as the absence of structure–performance prediction models, bottlenecks in large-scale preparation, and imperfections in in vitro and in vivo efficacy evaluation systems—and outlines future directions in precision design, green manufacturing, and industrial application, aiming to provide a theoretical reference for the in-depth development and efficient utilization of food microgels.