Probiotics like Lactobacillus rhamnosus GG (LRGG) offer health benefits but face reduced viability under harsh gastrointestinal (GI) conditions. Encapsulation improves stability, yet most studies rely on static GI models with a simplified environment that may overestimate survival. This study assessed LRGG survival using chitosan-coated alginate beads under both static and dynamic GI models, including peristaltic flow and continuous juice replenishment. Food matrices (casein, corn starch, and soybean oil) were tested in static models. Beads were prepared via extrusion and subjected to simulated gastric and intestinal digestion. After 2 and 4 h of digestion, casein preserved LRGG viability at 8.50 ± 0.11 Log CFU/g, compared to 5.81 ± 0.44 with starch and undetectable levels with soybean oil. Casein’s protective effect was attributed to its pH-buffering capacity, raising gastric pH from 2.5 to 4.6. Starch offered moderate protection, while soybean oil led to bead dissolution due to destabilization of the egg-box structure. Dynamic GI models showed greater reductions in LRGG viability than static models, emphasizing the need for physiologically relevant simulations. The results highlight the importance of selecting appropriate food matrices and digestion models for accurate probiotic assessment, supporting improved encapsulation strategies in functional food development.

Probiotics, such as Lactobacillus rhamnosus GG (LRGG), provide numerous health benefits, but their viability is challenged by harsh gastrointestinal (GI) conditions. En-capsulation is a promising approach to enhance probiotic stability; however, most studies rely on static in vitro GI models, which may overestimate probiotic survival due to the absence of dynamic physiological factors. This study evaluates the effects of food matrices (casein, corn starch, and soybean oil) and the impacts of dynamic in vitro GI models on LRGG survival and release during digestion simulations. Encapsulation was performed using alginate and chitosan-coated alginate beads by extrusion, and the viability of LRGG was assessed under simulated gastric and intestinal conditions. The results demonstrated that the presence of casein and corn starch improved LRGG survival compared to the control. Casein exhibited the strongest protective effect, likely due to its pH-buffering properties, while corn starch provided moderate protection. In contrast, soybean oil led to the complete dissolution of beads in the intestinal phase, resulting in no viable LRGG observed. Furthermore, dynamic GI models (DGDM and DIDM) showed greater re-ductions in LRGG viability than static GI models, highlighting the importance of using physiologically relevant digestion simulations. The findings suggest that evaluating probiotic encapsulation solely with static models may lead to the inaccuracy of survival and release rates. This study underscores the critical role of food matrices in probiotic protection and the necessity of dynamic GI models for accurate viability assessments, contributing to the optimization of probiotic encapsulation and assessments for functional food applications.