Optimal carvacrol loading was achieved by soaking MIL-100(Fe) nanoparticles into a 10 mg•mL -1 carvacrol ethanolic solution (20%) with a 5:1 carvacrol:MIL-100(Fe) molar ratio. First evidence of effective carvacrol loading was noticed by a colour change in the powder from orange to dark brown, respectively for bare MIL-100(Fe) and the collected carvacrol@MIL-100(Fe) composite (Figure ). Encapsulation completion was determined upon monitoring of the carvacrol sorption equilibrium over time in the collected composite material by gas chromatography (Figure ). A maximum loading capacity of 42% was reached after 5 days of immersion, with no further loading occurring up to 10 days (% calculated as loaded mass of carvacrol per total mass of dry composite), resulting in an encapsulation efficiency of 58%. This exceptional payload is, to the best of our knowledge, the highest carvacrol uptake onto a MOF obtained in a liquidphase encapsulation, surpassing the considerable 34% of carvacrol loading achieved in MIL-53(Al) by supercritical CO2 encapsulation. In addition, as compared to other classical carrier agents, the obtained carvacrol@MIL-100(Fe) composite is in a competitive position in terms of carvacrol loading, only being surpassed by carvacrol-loaded human serum albumin nanoparticles (Table ). Carvacrol loading was further evaluated by thermogravimetric analysis (TGA), X-ray powder diffraction (XRPD), N2 adsorption measurements and Fourier transform infrared (FTIR) spectroscopy. Thermal analysis (Figures and, Table ) of the loaded carvacrol@MIL-100(Fe) composite revealed a carvacrol content of 26.7 wt % (with respect to dehydrated MIL-100(Fe) nanoparticles). After removal of volatiles, in the 120-180 °C interval and at 230 °C, two separated mass losses of 8.3% and 18.4% can be respectively distinguished, which may be attributed to the release of carvacrol molecules differently interacting with the framework (i.e. physisorption vs chemisorption).