Selective Permeability of Volatile Organic Compounds in Candelilla Wax Edible Films

This study screens the permeability of volatile organic compounds (VOCs) through edible films made of candelilla wax and guar gum, offering new insights into their role as aroma and moisture barriers. Four formulations (0.2-0.4% wax, 0.4-0.8% gum, and 0.2-0.3% glycerol) were tested using a fractional factorial design. VOC fluxes (one ester, two aldehydes, two terpenes, and one lactone) were monitored via headspace solid-phase microextraction coupled to gas chromatography-mass spectrometry (HS-SPME/GC-MS) in a diffusion cell and modeled kinetically. Wax-rich matrices compacted the network, reducing initial VOC transmission by up to 60%, while glycerol fine-tuned micromobility and selectivity. The formulation containing 0.4% wax, 0.8% gum, and 0.2% glycerol minimized time-dependent flux acceleration and reduced the cumulative permeability of both polar (hexanal) and non-polar (limonene) markers by 80%. Aroma loss decreased across all blends, correlating with improved water vapor control. These results establish quantitative criteria for developing sustainable edible coatings that balance aroma retention, water-barrier performance, and mechanical flexibility.