Promising applications of cyclodextrins in food: Improvement of essential oils retention, controlled release and antiradical activity.

Essential oils (EOs) are gaining great interest as alternatives for harmful synthetic food preservatives. Due to their volatile nature, they could be applied in food packaging to improve food quality and extend shelf-life. To provide long-term effects of EOs by increasing their retention and ensuring controlled release of their components, they could be encapsulated in cyclodextrins (CDs). Herein, the ability of six CDs to retain nine EOs and to bind their individual components was investigated. Retention capacities and binding abilities of CDs were assessed by static headspace-gas chromatography (SH-GC) using a new validated "rapid method". The ability of CDs to generate controlled release systems was examined by multiple headspace extraction (MHE). Finally, radical scavenging activity of free and encapsulated EOs was evaluated. The highest retention capacity toward the studied EOs was obtained for β-CD and its derivatives (69-78%). Also, β-CD and its derivatives showed, with one exception, the highest Kf values for all the studied guests. In addition, encapsulation in CDs reduced the releasing rate of EO components (from 1.43 to 2.43-fold for β-CD/Satureja montana EO used as a model). Furthermore, the inclusion complexes showed higher ABTS(+) scavenging capacity than the free EOs. Results confirmed the usefulness of CDs as encapsulant for EOs and should encourage their application in food and as part of active packaging systems.