Ethanol-mediated synthesis of size-controlled γ-cyclodextrin metal-organic frameworks: Mechanistic insights into clove oil encapsulation, release and pork preservation.

Clove essential oil (CEO) possesses potent antioxidant and antimicrobial properties but suffers from high volatility and instability, limiting its application in food systems. A green, ethanol-mediated ultrasonic method was developed to synthesize biocompatible γ-cyclodextrin metal-organic frameworks (γ-CD-MOFs) with tunable particle size. Compared to conventional hydrothermal synthesis (3-5 μm), the ultrasonic approach yielded smaller, more uniform γ-CD-MOFs crystals (1-2 μm), which enhanced CEO loading (121 mg/g, +26 %) and improved structural stability. CEO encapsulation stabilized the framework through hydrogen bonding, van der Waals forces, and pore confinement, enabling sustained release at 4 °C and 25 °C. A clear size-dependent effect was observed, with smaller frameworks exhibiting superior loading efficiency and controlled release behavior. Molecular dynamics simulations elucidated the binding mechanism between CEO and the framework. CEO-loaded composites effectively inhibited microbial growth, extended pork shelf life, and exhibited good biocompatibility, offering a promising strategy for food preservation and controlled delivery of volatile bioactives.