Encapsulation of Origanum compactum Essential Oil in Beta-Cyclodextrin Metal Organic Frameworks: Characterization, Optimization, and Antioxidant Activity

The study is aimed at enhancing the physicochemical and antioxidant properties of encapsulated Origanum compactum essential oil (OCEO). In this context, a Clevenger apparatus was operated in the hydrodistillation process for O. compactum extraction, and the aroma profile of essential oil was investigated using GC/MS and GC/FID. The encapsulation process was based on beta-cyclodextrin (βCD) and metal organic frameworks (K-βCD-MOFs), analyzed by several techniques. Furthermore, the response surface design allows for improved encapsulation efficiency by optimizing OCEO/K-βCD-MOFs ( $w/w$ ) and water/ethanol ratios ( $v/v$ ). The antioxidant activity of the essential oil, both before and after the encapsulation, was evaluated through 1,1-diphenyl-2-picrylhydrazyl. As a result, the highest EE ( $35.34\pm 1.23\%$ ) was achieved in 1/12 and 4/5 for OCEO/K-βCD-MOFs and water/ethanol, respectively. The increase in thermal stability also occurred along with the encapsulation of O. compactum essential oil. Compared with the free form, the O. compactum essential oil encapsulated in K-βCD-MOFs gradually showed higher antioxidant activity.