Encapsulation of hexanal in Ca squarte MOF for active packaging

Abstract

Various high surface area porous materials have been widely researched for active food applications. Metal organic frameworks (MOFs), a vast family of porous compounds, have been derived by combining metal ions with organic linkers to form complex 3D structures. Pores present in these structures can be engineered to encapsulate active molecular species and control their release kinetics in the headspace of a product package system for shelflife extension. This work focuses on synthesizing calcium squarate acid MOF, also known as UTSA-280 using mechano-chemical synthesis process. Hexanal, a volatile antimicrobial compound, was encapsulated in UTSA-280 crystals via vapor diffusion process. The synthesized crystals were characterized before and after hexanal encapsulation using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), differential scanning calorimetry (DSC), and scanning electron microscopy (SEM). XRD patterns, FTIR and SEM images indicate that the UTSA-280 crystals were successfully synthesized. FTIR, TGA and DSC analyses conclude that encapsulation was successful, with TGA showing that approximately ~20 wt% hexanal was encapsulated in the UTSA-280 structure.