Antioxidant Activity and Quality Characteristics of Yogurt Added Green Olive Powder during Storage

The objective of this study was to determine the antioxidant and quality characteristics of yogurt added green olive powder stored at 4°С for 15 d. The following four groups were used in this study: Control group (GY0), Yogurt added with 1% green olive (GY1), with 3% green olive (GY3), and with 5% green olive (GY5). The more time of titratable acidity went by, the more it increased. Except GY0, viscosity tended to decrease in other groups (p>0.05), and the more time of syneresis went by, the more it increased, but GY3 of them showed the lowest syneresis. Lactic acid bacteria showed no significant with GY0 until 5 d, but after that, GY1, GY3 and GY5 showed lower than GY0. Yogurt added green olive showed darker color than GY0 (low L* and high a*). The antioxidant activity of GY5 was found to be the highest among the four groups at day 1 of storage. Total phenolic content, 2,2-diphenyl-1-picrylhydrazyl (DPPH) radical scavenging activity, and reducing power of GY5 was found to be the highest among the four groups at day 1 of storage which were 6.96 mg GAE/kg, 47.53%, and 0.57, respectively. In the sensory evaluation sweet and overall of GY3 indicated the highest score among the four groups. Results of this study demonstrated that green olive powder might be used to improve the antioxidant capacity and sensory characteristics of yogurt.