Curdlan, a functionally microbial extracellular polysaccharide with versatile food applications

Curdlan is a microbial extracellular polysaccharide composed of a linear β-1,3-glucan backbone with thermally irreversible gelation. Amid the global upsurge of plant-based and clean-label food demands, curdlan has attracted increasing academic and industrial attention in the food field due to its excellent safety and unique functional properties. Its rigid triple-helix structure confers distinctive gel behavior and high mechanical strength suitable for diverse food systems. This review systematically elucidates molecular structure, conformation, and gelation mechanism of curdlan, establishing the intrinsic link between its microscopic structure and macroscopic properties. Extraction and purification approaches, including alkaline-acid processes and emerging green methods, are discussed. Key findings emphasize that targeting the triple-helix conformation for structural regulation and composite design can improve its gel performance and expand application potential. Moreover, the challenges, solutions, and future opportunities of curdlan are discussed. This review provides a guidance for the research and development of curdlan in future food applications.