Cinnamaldehyde/β-Cyclodextrin Inclusion Complex Enhances Physicochemical and Antioxidant Properties of Edible Orally...

Despite the growing interest in orally disintegrating films (ODFs), developing soy protein isolate (SPI)-based ODFs with both rapid disintegration and high functional stability remains a challenge. This study developed a novel SPI-based ODF incorporated with a cinnamaldehyde/β-cyclodextrin (CA/β-CD) inclusion complex at varying concentrations (5-20%, w/w) to address this gap. The control ODF exhibited poor structural order, a slow disintegration rate, and weak antioxidant activity. The incorporation of an appropriate amount of CA/β-CD inclusion complex (10-15%) significantly improved the comprehensive properties of the ODFs. The inclusion complex facilitated the formation of an orderly, continuous network structure, leading to a substantial enhancement in tensile strength (TS), elongation at break (EAB), disintegration rate, thermal stability, and sustained antioxidant activity. An excessive inclusion complex concentration (20%) induced agglomeration, compromising the structural integrity and functionality of the ODF. FTIR and secondary structure analyses revealed that the enhanced hydrogen bonding between the CA/β-CD inclusion complex and the SPI matrix promoted the transformation of disordered protein structures into ordered conformations (β-sheets and α-helices). This structural ordering is the core mechanism driving the improved macroscopic physicochemical and functional properties of the ODFs. This study confirms that CA/β-CD inclusion complexes can enhance the performance of SPI-based ODFs and provide a highly promising delivery system for hydrophobic bioactive substances.