Comparative effect of gum arabic and psyllium husk on alginate hydrogels for Lactiplantibacillus plantarum encapsulation

This study examined the effects of gum arabic (GA) and psyllium husk (PH) as functional co-polymers in alginate (ALG) encapsulation matrices for Lactiplantibacillus plantarum, combined with inulin (IN), trehalose (TRE), or their mixture. Probiotic beads were produced by ionic cross-linking and evaluated during short-term refrigerated storage for morphology, metabolic activity, viability, membrane integrity, hydrophobicity, and intracellular trace-metal retention. PH-based hydrogels showed the highest viability, lowest membrane permeability, and improved retention of Mn, Fe, and Zn. These effects are consistent with the hydrated PH-rich network that may facilitate mass transfer and membrane stabilization under refrigerated storage. GA-based systems exhibited greater permeability and hydrophobicity but lower culturability, consistent with denser interfacial layers that may restrict diffusion. Microscopy supported visible morphological differences between hydrogel systems. A conceptual structure-function interpretation is proposed, and ALG-PH-IN and ALG-PH-IN/TRE emerged as the most effective formulations under the tested conditions.