Development and Morphological/Microstructural Characterization of a Novel Synergic Synbiotic Co-Encapsulated...

Kale, a nutrient-dense leafy green rich in bioactive compounds, has emerged as a promising prebiotic candidate for enhancing probiotic viability and functionality. This study investigated the effects of kale powder and its polyphenolic compounds on the growth and stability of a Lactobacillus spp. consortium. Growth kinetics experiments revealed that 1% kale powder significantly enhanced bacterial growth, with a pronounced increase observed after 5 h of incubation compared to the control. Furthermore, a synergistic synbiotic was successfully co-encapsulated using a 1.3% alginate-based matrix combined with 1% kale powder and Lactobacillus spp. consortium. Morphological characterization under varying temperature conditions demonstrated that co-encapsulated particles maintained structural integrity at 4°C and during freezing, while dehydration led to significant size reduction due to moisture loss. Encapsulation efficiency reached 93%, with the alginate matrix effectively protecting bacterial viability, as evidenced by only a 13% reduction in viability after storage at 4°C. Microscopic analyses confirmed the presence of polyphenols within the co-encapsulated system, with confocal microscopy revealing distinct autofluorescence attributed to phenolic compounds. Electron microscopy further showed that co-encapsulated particles remained intact under refrigeration and freezing but exhibited morphological changes after dehydration. Growth kinetics of the Lactobacillus spp. consortium in medium supplemented with kale-derived polyphenols indicated optimal growth at 0.4% concentration, while higher concentrations (0.6%) led to reduced growth, suggesting substrate inhibition. These findings highlight the dual role of kale polyphenols as prebiotic substrates and protective agents, underscoring their potential in developing stable and functional synbiotic delivery systems for probiotic applications.