Growth and Survival of Lactobacillus Acidophilus and Bifidobacterium Bifidum in Probiotic Yogurts Enriched by Barberry Extract

This study investigated the effect of functional properties of barberry aqueous extract in different concentration of 4 and 5% (w/w) on the growth and survival of probiotic cultures ( L. acidophilus, B. bifidum and an equal mixture of the two strains) in the set and stirred yogurt samples. The viable counts of L. acidophilus and B. bifidum in the set and stirred probiotic yogurts containing barberry extract were significantly higher than the control yogurt sample during the storage period. In a single strain of L. acidophilus , the highest viable populations of L. acidophilus in the set and stirred yogurts containing 5% of barberry extract were 1.15 × 10 8 and 1.1 × 10 8 on the first day, respectively. Additionally, L. acidophilus counts showed sharp decrease throughout the storage period but its counts held probiotic value of 10 6 log cfu/gr until Day 21, also the lowest viable count of B. bifidum (9.3 × 10 5 log cfu/gr) was observed in the control sample at the end of the 21 st day in a single strain of B. bifidum . Practical Applications Fruit and vegetable extracts are widely incorporated in food flavoring and are recently applied as growth‐stimulators of probiotic bacteria. The findings of this study indicated that probiotic yogurt samples fortified with barberry extract could be used as an adequate carrier of probiotic bacteria with bacterial counts more than the suggested level.