Effect of Using Russian Olive (Elaeagnus Angustifolia) Powder on Quality Properties of Non-Fat Set-Type Yoghurt

Russian olive, Elaeagnus angustifolia, is used in the treatment of various diseases because of its nutritional and pharmaceutical properties. The aim of this study was to evaluate the effect of using various amounts of Russisn olive powder on physicochemical, texture and sensory properties of set-type yoghurt produced from non-fat milk. Five yoghurt samples were manufactured from full-fat milk, non-fat milk and with addition of Russian olive powder in three different amounts of 10, 20 and 30 g/L to non-fat milk. Yoghurt samples were then stored in a refrigerator (4±1°C) for 22 days and their physico-chemical, texture and sensory properties were evaluated during storage. The results showed that using Russian olive powder caused significant changes (p<0.05) in physicochemical, texture and sensory properties of yoghurt samples. With addition of Russian olive powder, acidity, viscosity and water holding capacity decreased significantly in yoghurt samples, while pH and syneresis increased (p<0.05). On the other hand, while acidity and viscosity increased significantly during storage in all samples, pH, syneresis and water holding capacity decreased (p<0.05). In conclusion, using 10 g/L of Russian olive powder had the best physicochemical, texture and sensory result in manufacturing of non-fat yoghurt.