Humidity-responsive release of E-2-Hexenal based on Michael addition reaction for berry spoilage control

Abstract

Plants emit volatile compounds to defend against pathogens, and applying this mechanism in perishable food supply chains enhances preservation, safety, and sustainability. Here, we synthesized a sustained-release preservative, glutathione hexenal (Glut-SH-al), using the reversible Michael addition reaction between glutathione (GSH) and the natural compound E-2-hexenal. The reaction achieved 75.59 % efficiency, enhancing E-2-hexenal's thermal stability. This preservative ensures stable, controlled release of E-2-hexenal, with rates increasing with temperature and humidity. Glut-SH-al exhibits prolonged antifungal activity, inhibiting B. cinerea colony growth at 5 mg L-1 and completely inhibiting other fungi at 100 mg L-1, with sustained effects over time compared to pure E-2-hexenal. Glut-SH-al extended strawberry shelf life by inhibiting microbial growth, modulating key metabolites, and regulating genes (FaRAP, FaMYB10, FaPG1, FaPL) to reduce ripening and senescence. This sustained-release preservative adapts to various conditions, releasing E-2-hexenal in packaging to extend shelf life and enhance food safety, making Glut-SH-al a promising preservative for fruits, particularly berries.