Basil Seed Gum-Based Probiotic Films Containing Bacillus coagulans GBI-30, 6086 Spore and Vegetative Forms and Saccharomyces boulardii: Physicochemical Properties, Storage Stability, and Antibacterial Activity

This study investigated the development of basil seed gum (BSG)-based probiotic films as a sustainable alternative for food packaging and evaluated their physicochemical, structural, and biological properties. Following BSG extraction, glycerol-plasticized biopolymer films were prepared and incorporated with Bacillus coagulans GBI-30, 6086 (BC; spore and vegetative forms) and Saccharomyces (S.) boulardii. The films were then characterized in terms of moisture content, thickness, water solubility, water vapor permeability (WVP), color parameters, antioxidant capacity, and surface morphology. The results showed that probiotic incorporation influenced the barrier properties and microstructure of the films, with effects varying depending on the microbial form. Both spore and vegetative forms of BC resulted in higher WVP compared to that of S. boulardii and the control, while the vegetative form also led to the highest film thickness. In contrast, S. boulardii was associated with lower thickness and reduced permeability, suggesting the formation of a more compact matrix. During 21 days of storage, the spore form of BC maintained the highest viability (9.14 log CFU/g), indicating its superior stability associated with dormancy and resistance, whereas vegetative cells and S. boulardii exhibited markedly lower viability over time. All probiotic-containing films exhibited antibacterial activity against Klebsiella pneumoniae and Staphylococcus carnosus; however, the control formulation showed higher inhibition zones, indicating that the antibacterial effect was mainly associated with the intrinsic properties of the BSG matrix. Atomic force microscopy analysis demonstrated that probiotic incorporation increased nanoscale surface roughness without compromising structural integrity. Overall, these results highlight the potential of probiotic-enriched BSG films as an environmentally friendly active packaging system capable of enhancing food quality and serving as a carrier for functional bioactives.