Effect of Polydextrose and Galactofructose on the Viability of Probiotic Bacteria and Physicochemical and Sensory Properties of Synbiotic Kefir Drink

Introduction: Milk and fermented milk products play a major role in nutrition and human health at all stages of life. Kefir is one of the oldest fermented milk products. The aim of this study was to investigate the effect of polydextrose and galactofructose on the viability of probiotic bacteria and physicochemical and sensory properties of synbiotic kefir drink. Materials and Methods: Different concentrations (0.5 and 1%) of polydextrose and galactofructose (solely or in combination together) were used in kefir production. The samples were kept at 4˚C for 2 weeks and their microbial, physicochemical and sensory properties were evaluated. Results: The results showed that the use of polyextrose and galactofructose increased the viability of probiotic bacteria, pH and viscosity and decreased acidity of the test samples compared to the control sample (p≤0.05). In the kefir samples containing polyextrose and galactofructose, the viability of Lactobacillus acidophilus was more than Bifidobacterium lactis during storage. During storage, acidity and ethanol increased but pH decreased significantly (p≤0.05). The sample containing 0.5% polydextrose had the highest viability of probiotic bacteria on the 14th day. Sensory evaluation of kefir samples showed that the use of polyextrose and galactofructose caused a significant increase in overall acceptance score (p≤0.05). Conclusion: The sample containing 1% galactofructose and the sample containing 0.5% galactofructose + 0.5% polydextrose had the highest overall acceptance score. Since the number of probiotic bacteria in the above mentioned samples was 107-108 CFU/ml, these samples were selected as the best samples.