Effect of SaturejahortensisL. essential oil on physicochemical, textural and sensory properties and viability of starter culture of set yoghurt

This study was carried out to evaluate the effect of SaturejahortensisL. essential oil on the physicochemical,textural and sensory properties and viability of the starter cultureof set yoghurt during storage time (1, 11 and 21 days). Set yoghurt samples containing different concentrations of essential oil (0, 125, 250, 500 μg L-1) were prepared according to common yoghurt manufacturing method. The results indicated that there was no significant difference in viability of starter culture among samples contained various concentration of SaturejahortensisL.essential oil and control (P< 0.05). The yoghurt samples containing essential oil showed the lower acidity and higher pH values as compared to the control. By increasing the amount of essential oil, syneresis of samples decreased significantly (P< 0.05). There were significant differences (P ≤ 0.05) in the total acceptability of treated samples as compared with the control. The total acceptability of yogurt samples containing essential oil decreased with an increase in the essential oil concentration. Hardness and consistency significantly increased in all the yoghurt samples during the storage time. Furthermore, except the first day of storage, as the essential oil concentration in yoghurts increased, hardness and consistency significantly increased. As a conclusion, it was found that the yoghurt containing with SaturejahortensisL. essential oil (250 μg L-1) can be used to improve physicochemical and sensory properties of yoghurt and it does not affect the viability of the yoghurt starter culture.