Design of Multi-Component Beads (Alginate/Xanthan/Glycerol): Influence of Polymer Concentration on Lactobacillus acidophilus Viability and Release in Complex Food Systems

Abstract The growing interest in probiotic food matrices has driven research toward the development of innovative products that ensure the stability and functionality of beneficial microorganisms. This study investigated the effects of varying alginate concentrations (2, 4, and 6%) on the encapsulation efficiency, viability, and release control of L. acidophilus (LA) loaded in multi-component hydrogel beads for applications in peach juice and animal feed. Higher alginate concentrations improved capsule stability, probiotic protection, and survival. Increasing alginate from 2 to 6% reduced moisture content, increased swelling capacity, bead size, and encapsulation efficiency. LA viability exceeded recommended levels after the encapsulation process in all bead types, with 6% alginate providing the highest protection (≥ 80%) under gastrointestinal conditions. In peach juice, higher alginate concentrations (4% and 6%) significantly improved probiotic retention and decreased LA release. However, in feed, 2% of alginate capsules showed greater LA viability. The study highlights the importance of modulating alginate concentration to optimize the characteristics of the beads with LA , differentially influencing its viability and release pattern, depending also on the specific characteristics of the final food matrix. These findings are fundamental for the design of stable and functional foods in future.