Evaluation of Physicochemical Characteristics and Viability of Lactobacillus Acidophilus in Synbiotic Date Syrup Yogurt

The addition of date syrup might be considered as an ideal way to produce a functional food. This study was carried out to determine the effects of the addition of date syrup on sensory and physicochemical properties of synbiotic yogurt.

Date syrup was added at three different concentrations (5, 10 and 15% w/w). The samples were subjected to physicochemical analysis (pH, titrable acidity,syneresis and dry matter) and sensory evaluation (texture,formidability, flavor, color and overall acceptability) according to the standard methods.

Theresults showed that date syrup significantly increased the viability of the probiotics (P<0.05). The most count of probiotic bacteria was observed on the seventh day. After a few days the acidity was increased and the addition of each level of date syrup caused the acidity to be significantly increased (P<0.05). The results showed that pH value of the samples containing date syrup significantly decreased in the first and last days (P<0.05). There were significant differences in syneresis between control and date syrup yogurt during seventh and last days (P<0.05). The amount of dry matter was higher than control samples (P<0.05). Yogurt samples with 15% date syrup achieved the best organoleptic taste in sensory evaluation.

Utilization of date syrup in low fat yogurt especially at 15% concentration of it, caused an increase in the viability of Lactobacillus acidophilus and decreased syneresis and improved the sensory acceptability. Eventually, fortifying yogurt with date syrup produced acceptable yogurt with beneficial health effects.