Evaluation of Postbiotics from Lactiplantibacillus plantarum and Bacillus mojavensis Fermented in Aguamiel on Their Cytotoxic Effect in Breast Cancer Cells, Their In Vivo Effects, and Processing by Spray Drying

Background/Objectives: Postbiotics derived from beneficial bacteria have emerged as promising bioactive ingredients owing to their enhanced stability, safety, and functional versatility relative to live microorganisms. Methods: The present study was structured in two complementary stages: (i) biological characterization of liquid microfiltrates obtained from Lactiplantibacillus plantarum and Bacillus mojavensis fermented in aguamiel, and (ii) technological stabilization of these postbiotics through microencapsulation by spray drying, with a view to their potential incorporation into food matrices. Results&Conclusions: In the first stage, biological activity was assessed in vitro using MDA-MB-231 human breast cancer cells and in vivo in C57BL/6J mice, in order to evaluate safety and gastrointestinal effects. Both postbiotics significantly reduced cell viability relative to controls, consistent with antiproliferative activity. In vivo, no macroscopic intestinal damage was observed, supporting their safety profile. Histomorphometric analysis revealed preserved intestinal architecture, with elongation of villi and crypts and increased mucin 2 production, indicating strengthened mucosal barrier integrity; these effects were more pronounced in the Bacillus mojavensis-treated group. In the second stage, the spray-dried powders exhibited adequate physicochemical stability, supporting their potential application as functional food ingredients. The spray-dried powders exhibited adequate physicochemical stability, supporting their potential application as functional food ingredients.