The Effects of Gamma-Decalactone on the Physicochemical and Antimicrobial Properties of Pectin-Based Packaging Films

This study introduces an innovative strategy for active, biodegradable food packaging through the incorporation of gamma-decalactone (GDL), a natural aromatic compound with antimicrobial properties, into apple-pectin-based edible films. The addition of GDL significantly modified the film structure, resulting in enhanced light barrier properties (the opacity increased from 1.10 to 8.64 a.u./mm), a more porous microstructure (confirmed by SEM), and reduced tensile strength (from 13.84 to 5.68 MPa). The films also exhibited lower water vapour sorption (from 1.45 to 0.80 g/g dry matter (d.m.) and increased gas permeability. FTIR analysis confirmed interactions between GDL and the polymer matrix. The films with GDL added exhibited antimicrobial properties against various microbial species, such as bacteria, yeasts, and moulds. A 5% addition of GDL to the coating completely inhibited the growth of Bacillus subtilis bacteria and Yarrowia lipolytica, reducing the number of yeast cells by 3 log units (after 48 h of culture, from 7.11 ± 0.09 to 4.09 ± 0.27 log CFU/mL) and limiting Monilinia fructicola mycelium growth by 70%. These results highlight GDL's dual function as a natural aromatic and antimicrobial agent, supporting its potential application in sustainable packaging for perishable foods.