Formulation and characterization of ethanol–lemongrass oil emitters as antimicrobial active packaging

The application of appropriate postharvest technologies is essential to reduce deterioration and maintain the quality of fresh tropical fruits. Active packaging is an effective approach that enables the controlled release of antimicrobial agents to suppress fungal growth. This study developed an ethanol–lemongrass oil emitter (ELE) formulated with ethanol, silica dioxide, sodium stearate, and lemongrass (Cymbopogon citratus) essential oil at concentrations of 0 MIC, 0.5 × MIC, 1 × MIC, and 2 × MIC. Increasing essential oil concentration enhanced antifungal activity against Aspergillus niger, with the 2 × MIC formulation combined with an emitter mass of 2.5 g achieving complete fungal inhibition during storage. The antifungal effect was dose-dependent, as higher concentrations resulted in greater suppression of mycelial growth. Analysis of mass changes indicated that weight loss was mainly due to the volatilization of ethanol and essential oil components, rather than moisture absorption. The incorporation of silica dioxide and sodium stearate helped maintain the formulation's hydrophobic properties and ensure stable vapor release throughout storage. Overall, the ELE demonstrated strong antifungal efficacy and consistent controlled-release performance, highlighting its potential application for extending the shelf life of fresh tropical fruits.