Effects of neoagaroligosaccharides on quality characteristics and antioxidant activity of set yogurt

Yogurt is a popular dairy product with numerous health benefits. Neoagaroligosaccharides (NAOs), the enzymatic hydrolysates of agar, have exhibited great potential in yogurt fortification. This study aimed to explore the effect of NAOs addition on the bioactivity and sensory quality of set yogurt. The lactic acid bacteria count, physicochemical properties, texture, color, rheology, microstructure, and antioxidant properties of set yogurts were investigated. Results showed that NAOs addition could significantly increase lactic acid bacteria count in yogurt and enhanced its water holding capacity and viscosity. Rheological analysis showed that NAOs-fortified yogurt still maintains the characteristic of being mainly elastic. Microstructural observation revealed that NAOs addition decreased the gel pore structure and promoted the formation of larger protein clusters. The antioxidant activities of NAOs-added yogurt were also significantly improved. Combined with sensory evaluation results, we found that 6 mg/mL NAOs was the optimum concertation for yogurt fortification to achieve a balance of enhanced sensory quality and improved bioactivity. These findings are of interest to the application of NAOs in yogurt industry and the development of functional dairy products. • The set yogurt was supplemented with neoagaroligosaccharides (NAOs). • NAOs addition improved physicochemical and sensory properties of yogurt. • The antioxidant activity of yogurt was promoted by NAOs addition. • Interaction between NAOs and proteins improved yogurt gel network.