## 4 MOFs as Smart Carriers and Delivery Systems of Sensitive Volatile Compounds
### \(\gamma\)-CD-MOFs
Beyond the utilization of \(\gamma\)-CD-MOFs for the encapsulation and smart delivery of car-vacrol, this MOF has been found effective for the controlled release of various EOs, such as eugenol, cinnamaldehyde (CA), oregano essential oil (OEO), and thymol [139, 140, 143, 146]. Encapsulating these EOs in the pores of \(\gamma\)-CD-MOFs was found to be an effective solution for their antibacterial and antifungal activity, strengthening the profile of EOs as green substitutes of chemical compounds. In detail, encapsulation of eugenol enhanced its antifungal activity against _F. gaminearum_ towards the protection of wheat [139] while the loading of CA in the pores of \(\gamma\)-CD-MOFs enabled its sustained release over 15 days, which resulted in the effective inhibition of bacterial growth in fresh-cut canaloupes [140]. Also, the controlled release of OEO under the triggering presence of phosphate-buffered solution, presented a controlled release profile, bringing these systems to the forefront of various applications related to the agrifood industry, personal care and pharmaceuticals. Recent advancements related to innovative synthesis and encapsulation methods, lead to improved \(\gamma\)-CD-MOF application in the field of alternative preservation methods of crops and fresh-cut fruit. An important example towards this direction is the synthesis of nanosized \(\gamma\)-CD MOFs' particles employing an ultrasound-based technique. Through this approach, the efficient encapsulation of limonene was achieved. A high loading reaching almost 170 mg g\({}^{-1}\) was achieved combined with a content sustained release. This method combined with the deposition of \(\gamma\)-CD MOFs onto polycaprolactone (PCL) nanofibers, has resulted in a composite material with enhanced antibacterial activity against two of the most common pathogens, _E. coli_ and _S. aureus_. The resulting formulation was successfully applied for the preservation of fresh-cut apples [154]. Another important parameter regarding the behavior of \(\gamma\)-CD-MOFs in terms of encapsulating EOs, is the molecular docking within the cavities of \(\gamma\)-CD monomers as well as in the internal cavities of the MOF. This behavior has been studied monitoring the controlled release of limonene in such platforms emphasing on the effect of temperature and humidity in the process [154, 160]. Accordingly, the micro-encapsulation of citral in these systems has demonstrated the potential for high encapsulation capacity and prolonged-release kinetics in comparison to plain cyclodextrin systems [164]. Furthermore, citral encapsulation in \(\gamma\)-CD-MOFs was further studied employing a vapor diffusion approach. This formulation has demonstrated enhanced thermal stability, and a control release mechanism mainly based on hydrogen bonding interactions. Spectroscopic and computational studies have provided valuable insights into the host-guest interactions, with molecular docking revealing the preferred binding sites and stabilization energies [164]. The meticulous study of cyclodextrin based MOFs for the encapsulation and controlled release of volatiles as EOs has been also enriched by the exploration of the influence of the potassium salts used for their synthesis, both on the structure and consequently on the encapsulation properties of \(\gamma\)-CD-MOFs. The latter were synthesized using different potassium salts as, exhibiting improved stability and enhanced thymol encapsulation. The KAc-\(\gamma\)-CD-MOF analogue was found to have the largest encapsulation content. Additionally, the high-temperature adsorption method described in these works proves to be an efficient technique to prepared thymol-loaded \(\gamma\)-CD-MOFs' formulation, offering higher encapsulation efficiency and capacity compared to co-crystallization [165]. On the same ground \(\beta\)-CD-MOFs have been successfully employed for the stabilization of clove EO (CEO).