Effect of Incorporation of Mix Probiotic Culture in Sodium Alginate Film Characteristics: Antimicrobial, Physiochemical, Mechanical, and Barrier Properties.

Abstract

This study investigates the characterization and antimicrobial properties of sodium alginate (SA) films enriched with probiotic microorganisms, including Bifidobacterium animalis ssp. lactis B94, Lacticaseibacillus rhamnosus GG, and kefir cultures. The films were evaluated for their physicochemical, mechanical, and bioactive properties. The results showed that the addition of probiotics significantly influenced the films' thickness, moisture content, density, and water vapor permeability (WVP). Films containing a combination of kefir, B. lactis, and L. rhamnosus (SA-KLB) exhibited the highest thickness (100.00 ± 0.02 µm) and WVP (2.11 ± 0.00 g mm/h m² kPa), while control films (SA-C) had the lowest thickness (50.00 ± 0.00 µm) and WVP (1.45 ± 0.00 g mm/h m² kPa). The moisture content of probiotic films ranged from 20.28 ± 3.69% to 28.81 ± 0.61%, with SA-KLB showing the highest moisture retention. Mechanical properties, including tensile strength (TS) and elongation at break (E), were also affected by probiotic addition, with TS values ranging from 0.42 ± 0.06 to 1.49 ± 0.20 MPa and E values from 20.45 ± 3.60 to 28.62 ± 4.40%. Antimicrobial activity tests revealed that the films effectively inhibited pathogenic bacteria, with the strongest effect against Staphylococcus aureus (inhibition zones of 23.00 ± 1.41 to 24.75 ± 1.77 mm) and the weakest against Escherichia coli (15.50 ± 0.71 to 19.00 ± 1.41 mm). The viability of probiotics in the films after drying ranged from 81.79 to 90.57%, indicating good stability during the drying process. These findings suggest that probiotic-enriched SA films have potential as functional packaging materials, offering both extended shelf life and health benefits by delivering viable probiotics to consumers.