Effect of Plantago ovata Forsk seed mucilage on survivability of Lactobacillus acidophilus, physicochemical and sensory attributes of produced low-fat set yoghurt

Nowadays, consumers' attention to the functional foods has increased significantly. In this study, the effect of different concentration (0.5, 1, and 2%) of P.ovata Forsk seed mucilage (PFM) on survivability of L.acidophilus, physicochemical, and sensory attributes of produced low-fat yoghurt were investigated in 0, 7, 14, and 21 days of storage period. Results showed that at the beginning of the storage period, the number of L.acidophilus in yoghurt samples containing PFM was significantly higher than control sample. The highest number of L.Acidophilus was observed in yoghurt sample contain 2% PFM (6.68 log CFU/g) on the first day of storage period. The lowest decrease of L.Acidophilus (0.2 log CFU/g) was observed in the sample contain 2% PFM. Treatments containing PFM had lower pH and higher acidity than the control sample. Addition of PFM to the yoghurt samples increased water holding capacity (WHC) during storage period significantly while syneresis decreased. The highest WHC (89%) and the lowest syneresis (6%) were observed in yoghurt sample containing 2% PFM. Sensory evaluation results showed that the treatments containing PFM were not significantly different in taste, but the probiotic yogurt containing 1% PFM had the highest acceptability in terms of total appearance and texture. Evaluation of L, a, and b values indicated that yoghurt sample containing 2% PFM was significantly lower in L and b values and higher in a value than the control sample. Therefore, using P.ovata Forsk seed mucilage in yoghurt sample formulation improved the physicochemical attributes and probiotic survivability of produced yoghurt sample.