The effect of zinc and vitamin B12 together with thyme and <italic>Aloe vera</italic> extracts on the viability of <italic>Lactobacillus acidophilus</italic> LA‐5® and physicochemical properties of Iranian yoghurt drink (Doogh)

The possibility of a Bio‐Doogh production with active and live probiotic bacteria was investigated. In this study, the effect of zinc and vitamin B12 as micronutrients together with thyme and <italic>Aloe vera</italic> extracts at days 1, 11 and 21 of production on the development and viability of <italic>Lactobacillus acidophilus</italic>LA‐5<bold>®</bold> at 4 °C was studied. The addition of vitamin B12 (1.9 μg/L) and zinc (17.6 mg/L) increased the bacterial count of the probiotic strain; the effect of zinc was greater than that of vitamin B12. In addition, the data obtained indicated that the logarithmic bacterial count of the probiotic strain increased with addition of the thyme and <italic>Aloe vera</italic> extracts (10 mg/L). The simultaneous use of zinc and <italic>Aloe vera</italic> extract resulted in the highest probiotic bacterial count. Statistical analysis indicated that there were significant differences in the acidity and pH between the samples. The syneresis and odour of the test samples were different from the untreated samples. [ABSTRACT FROM AUTHOR]