Encapsulation of resveratrol in nanosheet structured sodium caseinate dialdehyde β-cyclodextrin conjugate with enhanced physicochemical properties

The poor solubility and stability of resveratrol (Res) represent significant obstacles to its utilization and efficacy. Encapsulating in sodium caseinate (NaCas) has also faced issues concerning low encapsulation efficiency and stability. This study presented the synthesis of a novel NaCas and dialdehyde β-cyclodextrin (DA-β-CD) conjugate through the Schiff base reaction using a wet-heating method, which was then utilized to encapsulate resveratrol. Results showed the DA-β-CD was formed in the form of needle-like crystals, whereas the NaCas-DA-β-CD conjugate had a nanosheet structure. The NaCas-DA-β-CD exhibited a substantial increase in surface hydrophobicity, emulsifying activity index, and emulsion stability index. The incorporation of resveratrol into NaCas-DA-β-CD demonstrated a consistent and uniform dispersion at the nanoscale level. It achieved an encapsulation efficiency of 96.8% and exhibited excellent chemical stability, which surpasses those of the NaCas system. Furthermore, the water solubility and antioxidant capacity of resveratrol in NaCas-DA-β-CD exhibited characteristics similar to those in NaCas. The compacted nanosheet structure of the Res-NaCas-DA-β-CD complex, as observed in TEM and SEM, is likely responsible for those enhancements. Hence, the DA-β-CD can serve as an effective polysaccharide for protein modification, while the NaCas-DA-β-CD conjugate can function as an innovative delivery carrier for resveratrol and other hydrophobic bioactives.