Humidity-responsive release of allyl isothiocyanate from MOF-199 (HKUST-1) for enhanced strawberry storage quality

Allyl isothiocyanate (AITC) was effectively encapsulated within HKUST-1. • HKUST-1@AITC exhibits a humidity-responsive release mechanism. • The vapor released from HKUST-1@AITC inhibits microbial growth. • HKUST-1@AITC significantly prolonged the shelf life of strawberries. Allyl isothiocyanate (AITC), a volatile compound predominantly found in mustard essential oil, has attracted significant attention as a potent natural antimicrobial agent for postharvest preservation of horticultural products. However, its high volatility, hydrophobicity, and pungent odor limit its application. In this study, a water-unstable metal–organic framework, HKUST-1 (MOF-199), was fabricated using a solvothermal method and functioned as a carrier of AITC. AITC was successfully encapsulated into HKUST-1 via impregnation, yielding HKUST-1@AITC with excellent humidity-responsive release behavior. As the relative humidity (RH) increased from 43% to 98%, the cumulative release rate of AITC rose from 41.06% to 54.82%. Moreover, HKUST-1@AITC and vapor-phase diffusion of AITC released from HKUST-1@AITC have shown to exhibit superior antibacterial activity. Application in strawberries showed that HKUST-1@AITC reduced weight loss by 25.05%, alleviated firmness loss by 39.89%, and effectively extended the storage duration to 7 days. Overall, HKUST-1@AITC shows potential use in active packaging to improve preservation of horticultural products.