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

Abstract

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 ( <a:math xmlns:a="http://www.w3.org/1998/Math/MathML" id="M1"> <a:mi>w</a:mi> <a:mo>/</a:mo> <a:mi>w</a:mi> </a:math> ) and water/ethanol ratios ( <c:math xmlns:c="http://www.w3.org/1998/Math/MathML" id="M2"> <c:mi>v</c:mi> <c:mo>/</c:mo> <c:mi>v</c:mi> </c:math> ). 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 ( <e:math xmlns:e="http://www.w3.org/1998/Math/MathML" id="M3"> <e:mn>35.34</e:mn> <e:mo>±</e:mo> <e:mn>1.23</e:mn> <e:mi>%</e:mi> </e:math> ) 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.