Engineering a Thermoresistant and Adaptable Nondigestible Carbohydrate Matrix With Bacillus clausii for Controlled Probiotic Delivery in Food Matrices

Probiotic microencapsulation systems have traditionally prioritized biological parameters, often neglecting the role of structural and physicochemical characteristics in determining functional performance. This gap limits predictive design, particularly because probiotics can influence wall material architecture through structural and interfacial interactions. This study evaluated these interactions between Bacillus clausii and nondigestible carbohydrate matrices (resistant maltodextrin, alginate, and inulin) to enhance the thermal and mechanical stability of a probiotic delivery system. Microencapsulation of Bacillus clausii was carried out using spray drying, followed by the assessment of physicochemical, microstructural, vibrational, spectroscopic, crystallographic, and thermal properties, as well as viability under simulated gastrointestinal conditions. Dynamic light scattering (DLS) and morphology confirmed successful encapsulation, while thermal cycling revealed distinct structural recovery behaviors linked to probiotic-matrix interactions, reflected in particle size and zeta potential changes. IFourier-Transform Infrared Spectroscopy (FTIR) and UV-Visible (UV-Vis) spectroscopy analyses indicated molecular-level modifications, including altered glycosidic bonds and polysaccharide rearrangements, which were supported by the amorphous architecture identified through X-ray diffraction (XRD), favoring water sorption and controlled release. Thermal properties revealed a nonreversible phase transition near 59°C, suggesting matrix reorganization and enhanced enthalpic stability when probiotics were present. High viability under gastrointestinal simulation reached 9.85-10.25 Log colony-forming units (CFU)/g. Together, these findings reveal that B. clausii functions not merely as biological cargo but as a structural comodulator of the matrix, offering an advantage over previous encapsulation studies that considered probiotics as passive components.