Abstract
The effect of a prebiotic (fructooligosaccharides) or a synbiotic components (prebiotic and probiotic) on the viability, proteolysis and antioxidant properties of probiotic and synbiotic yogurt during 28 days of storage at 4 °C has been investigated. Yogurt starters in conjunction with either probiotic bacteria Lactobacillus plantarum CFR 2194, Lactobacillus fermentum CFR 2192 and/or fructooligosaccharides (FOS) were used for yogurt preparation. Titratable acidity and pH of all yogurt samples followed a similar pattern of increase or decrease during storage. Proteolysis in synbiotic yogurts was found to be significantly (P < 0.05) higher in comparison with that of control. The addition of prebiotics had no effect (P = 0.17888) on the viability of yogurt starters during cold storage. No observable changes in the viability of probiotic cultures in probiotic groups. However, supplementation of FOS affected the growth significantly (P < 0.05) in promoting the growth of L. plantarum and L. fermentum. Antioxidant activities, the index of nutritional value of yogurt, were monitored. Results showed that the DPPH-radical-scavenging activity (85 %) in synbiotic yogurt containing L. plantarum and FOS was significantly higher (P < 0.05) in comparison with that of control yogurt (72 %). Total phenolics and the ferric reducing power were highest in synbiotic yogurts in comparison with that of other test samples during the entire period of storage. Addition of selected probiotics with FOS thus resulted in an improved functionality of yogurt.