Molecular design of sustainable bio-adhesives: Chlorogenic acid as a key modulator of structure and functionality soy...

A plant-based adhesive composed of soy protein isolate (SPI), low-ester pectin, and chlorogenic acid (CA) was developed for bonding plant-based meat. The effects of varying CA concentrations (0-2.0 wt%) on rheological properties, thermal stability, and molecular structure of adhesives were systematically examined. Results showed that CA improves the rheological properties and thermal stability. It also altered the secondary structure, affecting the proportions of α-helices, β-turns, and β-sheets. The phenolic and carboxylic groups in SPI and pectin formed extensive hydrogen bonds with CA, especially at 1.0 wt%, resulting in the most uniform and compact microstructure. Structural analysis further revealed that covalent intermolecular interactions exposed tyrosine and tryptophan residues, promoting the formation of a stable adhesive network. These results highlight 1.0 wt% CA as the optimal concentration for maximizing adhesive performance and provide valuable insights for the design of innovative, food-grade adhesives in plant-based applications.