The Effect of Cuminum Essential Oil on Rheological Properties and Shelf Life of Probiotic Yoghurt

Background: Antimicrobial and antioxidant properties of the essential oils (EOs) are important in food industry. This study investigated the effects of EO from Cuminum cyminum on the preservation of yogurt containing Streptococcus thermophilus, Lactobacillus bulgaricus, and Bifidobacterium bifidum. Methods: The yogurt samples’ biological, physicochemical, and sensorial characteristics were evaluated at three levels of 1%, 2% and 3% of EO during the storage (7, 14, and 21 days). Results: The bacterial activity declined significantly in all samples during the storage (P < 0.05). Adding EO decreased the rate of bacterial growth of both probiotic and starter strains over 21 days. The titratable acidity (TA) and syneresis were increased (P < 0.05), while the pH levels were decreased (P < 0.05) during the storage. The highest viscosity was 8600 mili paskal secent (mPa.s) in control sample in the first day and 5700 mPa.s for 1% cuminum cyminum essential oil (CEO) on the 21st day. The CEO had no effects on flavor, odor, and overall acceptability. Conclusion: Generally, the high level of phenols influenced the biological, physicochemical, and rheological properties of bioyogurts positively.