This study aimed to develop synbiotic edible films based on fish gelatin containing
Lacticaseibacillus rhamnosus GG, evaluating the impact of different prebiotics (inulin and fructooligosaccharides, FOSs) and structuring polysaccharides (pectin and alginate) on their physical, mechanical, thermal properties, cell viability, and in vitro
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This study aimed to develop synbiotic edible films based on fish gelatin containing
Lacticaseibacillus rhamnosus GG, evaluating the impact of different prebiotics (inulin and fructooligosaccharides, FOSs) and structuring polysaccharides (pectin and alginate) on their physical, mechanical, thermal properties, cell viability, and in vitro gastrointestinal behavior. Seven film formulations were prepared from fish gelatin solutions (3%, w/v) containing glycerol (30%, w/w, as plasticizer), with the addition of prebiotics (inulin or FOSs, 1:1 w/w to gelatin), either alone or in combination with pectin (1%, w/v) or alginate (0.5%, w/v). Specifically, F1 contained gelatin, glycerol, and
L. rhamnosus GG (control); F2 and F5 included inulin or FOSs, respectively; F3 and F6 combined inulin or FOSs with pectin; and F4 and F7 combined inulin or FOSs with alginate. After incorporation of the probiotic, the solutions were cast and dried at 37 °C for 24 h. The incorporation of prebiotics and polysaccharides significantly influenced probiotic viability after film drying (
p < 0.05). The control formulation (F1) showed the highest reduction (26.10%), while F4 (inulin + alginate) and F7 (FOS + alginate) exhibited the lowest losses of 10.41% and 10.98%, respectively. These films also demonstrated better performance during simulated digestion, with F7 showing the smallest reduction after 6 h (0.5 log), maintaining 7.0 colony-forming units per gram (CFU g
−1), which is considered adequate for functional effects. Physically, the films varied in solubility (27.50% to 41.37%), thickness (0.085 to 0.095 mm), water vapor permeability (WVP) (8.17 to 11.75 g·mm/m
2·d·kPa), and moisture content (13.47% to 17.50%). Mechanically, F4 showed the highest tensile strength (24.5 MPa), while F1 had the highest elongation at break (62%). During storage, F7 and F4 showed the lowest viability losses (29.8% and 29.4%, respectively) under refrigeration. Overall, the results indicate that the association of prebiotics with structuring polysaccharides improves stability, cellular protection, and functional performance of the films.
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