Boosting longan seed starch-flavonol complex formation via cold plasma: Structural, functional, and mechanistic...

This study systematically investigated how cold plasma (CP) enhances the formation of longan seed starch-flavonol complexes (LS-Fls) to elucidate the underlying structure-property relationships. Results demonstrated that flavonols (FLs) facilitated longan seed starch (LS) rearrangement via non-covalent interactions, forming non-inclusion complexes that significantly increased structural order, crystallinity, branching degree, and thermal stability while reducing digestibility. These changes exhibited significant positive correlations with the number of hydroxyl groups on the B ring of flavonols. Incorporating FLs during CP treatment induced more profound modifications than complexation alone. CP etching caused morphological alterations while partially restoring local molecular order. Furthermore, depolymerization emerged as a primary CP mechanism, evidenced by reduced amylose content and storage modulus. Notably, the resistant starch content in the myricetin-complex (CP-LS-Myr) reached 35.33%, significantly higher than complexes CP-LS-Que (31.50%), CP-LS-Kae (30.69%), CP-LS (28.16%) and LS (23.84%). Consequently, the combined CP-FLs modifications enhanced starch functionality, particularly rheological properties and digestibility. This study demonstrates that integrating CP and FLs offers a simple, green approach to tailor starch for food applications requiring controlled digestibility and viscosity stability during storage.