Antioxidant, Syneresis, and Sensory Characteristics of Probiotic Yogurt Incorporated With Agave tequilana Aqueous Extract

Background: The growing consumer interest in healthy food has encouraged the industry to search for products that exhibit additional benefits over nutritional value. Yogurt is the best carrier for beneficial nutrients such as probiotics and antioxidants. Agave tequilana is a plant that contains phytochemicals comprising flavonoids that show antioxidant activity. Objectives: In this work, the effects of incorporating A. tequilana aqueous extract (ATAE) on the antioxidant properties, syneresis, and flavor of probiotic yogurt were investigated. Methods: Radical scavenging ability was evaluated against the 2,2-diphenyl-1-picrylhydrazyl (DPPH). Amounts of total phenolic compounds (TPC) were determined using the Folin-Ciocalteu method. Syneresis was determined using the centrifugal technique. The sensory evaluation was carried out using a 5-point hedonic scale. Results: The addition of ATAE in yogurts exhibited a dose-dependent relationship and had significantly (P≤0.05) higher TPC and DPPH scavenging ability than the control yogurts. The TPC and DPPH scavenging properties of 0.5%, 1%, and 1.5% ATAE-fortified yogurts were 389.9, 629.2 and 905.6 mg GAE/kg yogurt and 283, 480, and 617 mg BHT eq./kg yogurt, respectively. The addition of ATAE increased the syneresis of yogurt samples (P≤0.05). Although the sensory properties of synbiotic yogurt samples were lower than plain and probiotic treatments, their scores were still above the acceptable level. Conclusion: As the results of this study indicated, it is recommended to improve the antioxidant properties of the yogurt by incorporating AEAT and its potential application as a functional food formulation.