The survival of probiotic Bifidobacterium bifidum and Lactobacillus acidophilus in synbiotic yogurt enriched with Agave tequilana aqueous extract

In this study the effect of incorporation of aqueous extract of Agave tequilana (AEAT) on viability of Bifidobacterium bifidum and Lactobacillus acidophilus was investigated. No reduction of cell viability was seen in any treatment groups of L. acidophilus during the storage time. A statistically significant increase in L. acidophilus count was found in synbiotic yogurt samples containing 1 and 1.5% concentrations of the extract at day 21 of storage compared to the first day (p<0.05). The viability of B. bifidum remained unchanged in control probiotic yogurt during the storage, while there was a viability increase of 1, 1.2 and 2.4 log cycles in synbiotic yogurt samples containing 0.5, 1 and 1.5% concentrations of the extract during the storage, respectively. The final pH at day 21 ranged from 3.98-4.15. The pH of all yogurt samples was decreased as a function of time, while no statistically difference in pH was seen between different groups (p>0.05). All the yogurt samples revealed an increase in titratable acidity as a function of storage time.  In conclusion, as the results of this study indicated improvement of probiotic bacteria in yogurt incorporated with AEAT, its potential application as a functional food formulation is recommended.