Gellan-aloe vera aerogels for active food packaging: Structural properties and antimicrobial performance

In this study, aerogels were developed from low-acyl gellan gum (LAGG) and aloe vera gel (AVG) through a centered composite design to increase their structural and antimicrobial performance for food packaging applications. The effects of pH (1, 4, and 7), the LAGG/AVG ratio (66/33, 50/50, and 33/66), and the solid content (0.25, 0.50, and 0.75 % w/v) were evaluated. The optimal formulation, pH 1, 66/33 LAGG/AVG ratio, and 0.75 % v/w solids, presented low volumetric shrinkage (30.9 %), high porosity (90 %), low density (0.030 g/cm³), high hardness (4.1 N), and thermal stability, with glass transition (T_g) and melting (T_m) temperatures of 54.4 °C and 74.3 °C, respectively. Eugenol-loaded aerogels based on this formulation effectively inhibited the growth of Escherichia coli and Staphylococcus aureus after 60 and 40 min, respectively, via headspace release over agar plates without direct contact. These findings support the potential of LAGG-AVG aerogels as natural polymer-based carriers for volatile antimicrobial agents in active packaging systems.