Selenuim-enriched probiotic fermented milk drink (DOOGH): characteristics and survival microorganisms

Selenium (Se) is considered as an essential element for human body. Selenized probiotic fermented milk drink (DOOGH) as a functional beverage to increase Se available in body. The predominate sugar, protein and mineral ion of Iranian yoghurt drink (DOOGH) are lactose, casein and calcium, respectively. Different levels of  Selenium (2.5 – 3- 3,5-  4 and 4.5) is prepared and its suitability based on the sensory attributes and survival of starter and probiotic microorganisms in the presence of Se are evaluated. Result showed that the concentration sensory features (color, odor and flavor) of Se-enriched DOOGH were not affected at Se concentration levels below 5 mg L-1 for 4 weeks. The colony forming units (cfu) of Streptococcus thermophilus (starter bacteria) and strains Lactobacillus acidophilus  and Lactobacillus casei (probiotic bacteria) of the Se-enriched DOOGH with different concentrations of Se and control sample (without Se) decreased during 4 weeks. There was significant (p< 0.05) decrease in cfu of all bacterias after week 3. Population of microorganisms significantly (p< 0.05) decreased at higher concentrations of Se (4 and 4.5 mgL-1).