Physicochemical, Antioxidant, Microbial, and Sensory Analysis of Buffalo Milk Stirred Yogurt Fortified With Cactus Pear ( <scp> <i>Opuntia ficus indica</i> </scp> ) Pulp

The current study aimed to evaluate the impact of incorporating cactus pear pulp (CPP) at various concentrations (2%, 4%, 6%, 8%, and 10% w/w) levels on the physicochemical, functional, LAB, and sensory attributes of stirred buffalo milk yogurt during refrigerated storage over 21 days. The results revealed that all measured qualitative attributes of yogurt samples were significantly (<i>p</i> < 0.05) affected by the CPP concentrations and storage durations. The study showed that adding CPP to yogurt led to an increase in pH and a decreasing trend in acidity. The CPP yogurt samples (10% CPP) exhibited the highest pH (4.97) on Day 1. Significantly high (<i>p</i> < 0.05) titratable acidity was recorded in the control sample on Day 21 during storage. Syneresis susceptibility was reduced in 10% CPP added yogurt samples and demonstrated the lowest values (30.36) on 1st day of storage. Significantly (<i>p</i> < 0.05) enhanced water-holding capacity (68.59%) in the yogurt supplemented with 10% CPP was observed. Increasing the amount of CPP in yogurt resulted in a constant increase in water-holding capacity, while simultaneously lowering syneresis across the storage period. Functional parameters including total phenolic content and antioxidant activity showed a significant dose-dependent increase and decreasing trend as a function of storage period. On the first storage day, yogurt samples having 10% CPP had the highest total phenolic content (8.22 mg GAE/100 g) and DPPH scavenging activity (83.45%). The viable count of LAB showed a substantial rise in CPP added yogurt samples on 1st day of storage, while a gradual decline was noted over the storage period in all treatments. Significant differences in sensory properties were observed among the samples; however, yogurt containing 4% CPP emerged as the most acceptable formulation based on sensory profiling. The findings concluded that adding CPP considerably enhanced the physicochemical, functional, LAB, and sensory attributes of yogurt samples.