Encapsulation Efficiency and Functional Stability of Cinnamon Essential Oil in Modified β-cyclodextrins: In Vitro and In Silico Evidence

Abstract

Essential oils (EOs) have good natural antioxidant and antimicrobial properties; however, their volatility, intense aroma, poor aqueous solubility, and chemical instability limit their applications in the food industry. The encapsulation of EOs in <i>β</i>-cyclodextrins (<i>β</i>-CDs) is a widely accepted strategy for enhancing EO applications. The complexation of cinnamon essential oil (CEO) with five types of <i>β</i>-CDs, containing different substituent groups (<i>β</i>-CD with primary hydroxyl, Mal-<i>β</i>-CD with maltosyl, CM-<i>β</i>-CD with carboxymethyl, HP-<i>β</i>-CD with hydroxypropyl, and DM-<i>β</i>-CD with methyl), inclusion process behaviors, volatile components, and antioxidant and antibacterial activities of the solid complexes were studied. The CEOs complexed with Mal-<i>β</i>-CD, CM-<i>β</i>-CD, and <i>β</i>-CD were less soluble than those complexed with DM-<i>β</i>-CD and HP-<i>β</i>-CD. Molecular docking confirmed the insertion of the cinnamaldehyde benzene ring into various <i>β</i>-CD cavities via hydrophobic interactions and hydrogen bonds. GC-MS analysis revealed that HP-<i>β</i>-CD had the greatest adaptability to cinnamaldehyde. The CEO encapsulated in <i>β</i>-, Mal-<i>β</i>-, and CM-<i>β</i>-CD showed lower solubility but better control-release characteristics than those encapsulated in DM- and HP-<i>β</i>-CD, thereby increasing their antioxidant and antibacterial activities. This study demonstrated that <i>β</i>-, Mal-<i>β</i>-, and CM-<i>β</i>-CD were suitable alternatives for the encapsulation of CEO to preserve its antioxidant and antibacterial activities for long-time use.