Obtenção de sucos de frutas potencialmente pós-bióticos por termossonicação e processamento térmico e seus efeitos na microbiota intestinal humana

Abstract

The transition from probiotics to postbiotics has gained prominence in the search for more stable functional foods. This study aimed to develop, model inactivation kinetics, and evaluate the functional signatures of postbiotic fruit-based beverages fermented by Lacticaseibacillus casei NRRL B-442, comparing the efficacy of thermal processing (TH) and thermosonication (TS). The methodology encompassed the lactic acid fermentation of acerola and orange juices, which were subsequently subjected to thermal (TH, at 80 °C) and thermosonic (TS, at 60 °C) inactivation. Physicochemical stability, cell viability, antibacterial potential, and inactivation kinetics under different reactor geometries were evaluated, along with the modulation of the human gut microbiota through anaerobic colonic fermentation. The results indicated that both TS and TH effectively inactivated the probiotic, preserving phenolic compounds, antibacterial activity, and antioxidant capacity over 35 days under refrigerated storage (4 °C). Kinetic modeling suggested that thermal processing followed linear kinetics, while TS efficiency depended on the reactor geometry. The use of larger glass reactors (250 mL capacity) seems to have optimized the acoustic flow, providing a linear and faster inactivation than the thermal method, whereas confined steel reactors (10 mL) generated a resistant tailing effect. During colonic fermentation, it was observed that the inactivation method influenced the matrix behavior. The TH-80 processing generated a butyrogenic postbiotic, possibly associated with the suppression of the Proteobacteria phylum and the enrichment of genera of interest (Bacteroides and Phascolarctobacterium). Conversely, the TS-60 juice favored the expansion of the Fusobacterium genus, raising the hypothesis that cavitation-mediated cell lysis may have made intracellular compounds more available to opportunistic microorganisms. The findings suggest that thermal processing acts as a promising strategy for developing postbiotics with the potential to assist in mitigating colonic dysbiosis. Thermosonication constitutes a rapid technology, provided that the reactor geometry ensures adequate acoustic conditions; however, the alterations promoted in the matrix require studies under in vivo conditions.