LAUSR

In the present work, physicochemical, sensory characteristics and viability of Bifidobacterium bifidum and Lactobacillus casei of probiotic yogurt using dill (Anethum graveolens) essential oil (DEO) (50 and 100 ppm) were investigated at 4°C for 21 days. Alterations in amount of fat and protein of yogurt treatments during storage time were not significant. The viability of B. bifidum and L. casei increased up to the 2nd week of storage and then decreased by the end of the storage period. Generally, samples with incorporated 100 ppm DEO had the highest number of probiotic bacteria on the last day of storage, 7.81 and 7.92 CFU/g for L. casei and B. bifidum, respectively. pH and titratable acidity values were decreased and increased, respectively, over the time for all samples. Yogurt with incorporated 100 ppm DEO achieved higher sensory scores compared to other yogurt samples. Therefore, the current results confirmed that the addition of probiotic and DEO improved the physicochemical and sensory characteristics of yogurt. PRACTICAL APPLICATIONS: Yogurt undergoes sensory, chemical changes and microbial growth during refrigerated storage. Bifidobacterium bifidum and Lactobacillus casei are generally applied as probiotic species in milk products. Dill essential oil (DEO) is used in food industries to extend the shelf life of the foods with desired organoleptic properties. This work recommends that DEO can be successfully used as a safe and natural source in the production of probiotic yogurt.