Formulation and characterisation of functional dietary yogurt with <i>Lactococcus lactis</i> R7 and <i>Psidium cattleianum</i> extract: evaluation of probiotic viability and physicochemical, bioactive and sensory properties

Functional foods enriched with probiotics and bioactive compounds are promising for health promotion and chronic disease prevention. This study developed a functional yogurt containing Lactococcus lactis subsp. lactis R7 and red cattley guava (Psidium cattleianum) extract, recognised for probiotic and antioxidant properties. The product was evaluated for physicochemical composition, bioactive profile, probiotic viability during storage and simulated gastrointestinal conditions, sensory acceptance, and microbiological quality. Guava extract improved the nutritional profile by increasing protein and carbohydrate contents and reducing fat, while significantly enhancing phenolic compounds, anthocyanins, and antioxidant activity. L. lactis R7 remained viable above 6 log CFU g−1 for 14 days and tolerated gastrointestinal simulation. Sensory acceptance was high, supporting the yogurt’s potential as a functional food vehicle for probiotics and bioactive compounds.