Abstract

Effect of Spinacia oleracea extract on physicochemical, phenolic content, antioxidant activity and microbial properties of yogurt

Author(s): Jafar Hayaty Nejad, Ali Mohamadi Sani, Mohammad Hojjatoleslamy

Yogurt flavored with kiwi flavor (1, 2 and 4%) and colored with spinach extract (1.25, 2.5 and 4%) and a control yogurt (no kiwi flavor or spinach extract) were evaluated for some chemical characteristics, viscosity, syneresis, L*, a* and b* color values and microbial properties at sevenday intervals for 21 days. Significant differences were found between the control and kiwi-spinach yogurt with respect to syneresis and viscosity characteristics (P<0.05). Increasing the amount of spinach extract in yogurt resulted in a decrease in L*, a* values of yogurt, and increase in b* color, syneresis, total phenolic content, antioxidant activity, titratable acidity and viscosity parameters (P<0.05). During the storage period, pH decreased but titratable acidity, syneresis and viscosity values of yogurt samples increased continuously (P<0.05). Storage affected LAB count significantly (P<0.05).