INVESTIGATION OF NUTRITIONAL VALUE, ANTIBACTERIAL AND ANTIOXIDANT POTENTIAL OF HERB-FORTIFIED YOGURT PREPARED BY LACTOBACILLUS AND BIFIDOBACTERIUM

Background: Probiotics and functional foods play a critical role in improving human health by modulating gut microbiota and enhancing immune responses. Yogurt fortified with medicinal herbs represents a promising strategy to improve nutritional quality and biological activity. Mentha piperita (mint) is rich in bioactive compounds with known antioxidant and antimicrobial properties. Objective: This study aimed to evaluate the nutritional value, antioxidant activity, and antibacterial potential of Mentha piperita– fortified yogurt prepared using Lactobacillus and Bifidobacterium isolates. Methods: Probiotic strains were isolated from locally available yogurt and used to prepare plain and mint-fortified yogurt. The fortified yogurt was produced by adding aqueous mint extract at different concentrations. Nutritional composition (protein, fat, carbohydrates, calcium, vitamin D, and sodium) was analyzed. Antioxidant activity was assessed using the DPPH free-radical scavenging assay. Antibacterial activity against Escherichia coli, Salmonella spp., Enterococcus spp., and Staphylococcus aureus was evaluated using the agar well diffusion method. All experiments were performed in triplicate. Results: Herb-fortified yogurt showed significantly higher nutritional values compared to plain yogurt, including increased protein, fat, carbohydrates, calcium, and vitamin D contents. The DPPH assay revealed strong antioxidant activity, with maximum inhibition observed at higher concentrations of fortified yogurt. Antibacterial testing demonstrated notable inhibitory effects against all tested pathogens, with the strongest zones of inhibition observed against E. coli and Salmonella spp. The fortified yogurt also showed enhanced activity when combined with selected antibiotics. Conclusion: Mentha piperita–fortified probiotic yogurt exhibited superior nutritional quality, strong antioxidant capacity, and significant antibacterial activity compared to plain yogurt. These findings support the potential of herb- fortified yogurt as a functional food for promoting health and preventing enteric infections.