In vitro inhibition of Streptococcus mutans by probiotic yogurt fortified with Lactobacillus paracasei and Sargassum angustifolium protein hydrolysate: a functional yogurt for teeth decay prevention

Background and Objectives: Probiotic yogurts enriched with Lactobacillus paracasei (L. paracasei), protein hydrolysates derived from Sargassum angustifolium macroalgae (SAPH), and encapsulated SAPH were formulated to inhibit Streptococ- cus mutans (S. mutans), the primary bacterium responsible for dental caries. Materials and Methods: The yogurt samples were evaluated for physicochemical, microbiological, and sensory character- istics. Results: On day 21, the yogurt supplemented with L. paracasei demonstrated the greatest titratable acidity (97.35°D), the lowest pH value (4.24), reduced syneresis, and enhanced antioxidant, antihypertensive, and rheological properties. In terms of antibacterial activity, the lowest S. mutans count was detected in formulations containing free SAPH, either alone or in combination with L. paracasei. Conversely, yogurts formulated with encapsulated SAPH exhibited higher survival rates of both L. paracasei and S. mutans compared to those containing the free form of SAPH. Conclusion: The findings indicated that although the probiotic yogurt containing free SAPH was more effective in reducing S. mutans levels within the yogurt matrix, the encapsulated form achieved an acceptable level of antibacterial activity while contributing to improved sensory acceptance.