Production of 3D-printed functional milk chocolate with postbiotics of Bifidobacterium animalis ssp. lactis BB-12

The present study was conducted to evaluate the impact of three different concentrations of Bifidobacterium animalis ssp. lactis BB-12 postbiotics (0.5, 0.75 and 1%) on the functional and physicochemical properties of 3D-printed milk chocolate. Supplementation of postbiotics resulted in significant changes in chocolate attributes in a concentration-dependent manner. The antioxidant capacity was enhanced at all concentrations, with the highest activity observed at 1%, despite minimal changes in total phenolic content. This suggests that the improved antioxidant capacity was largely due to non-phenolic compounds. Rheological and textural properties were significantly influenced; 0.5–0.75% of postbiotics reduced chocolate hardness (1377–1488 g) and enhanced its flowability, whereas 1% postbiotics increased chocolate hardness by up to 2558 g and viscosity, which may be associated with changes in the physical organization of the chocolate matrix. The thermal stability remained largely unchanged (T p ≈ 34.4–35.7 °C; T o ≈ 28–31 °C), indicating that postbiotics incorporation did not affect the cocoa butter crystallizing behavior. Significant differences in color ( L * reduced, a * increased) occurred at 0.5–0.75% concentrations. In general, 3D-printed functional milk chocolate enriched with B. lactis BB-12 postbiotics can be considered a promising approach for incorporating bioactive ingredients into confectionery products.