Comparison of the effect of extracted inulin from native chicory root with commercial inulin on the viability of probiotics and physicochemical, rheological and sensory properties of synbiotic yogurt

The purpose of this study was to compare the effects of extracted inulin from chicory root and commercial inulin on synbiotic yogurt properties during 21 days at refrigerator storage. Inulin powder from chicory root (0, 1.5, 3 and 4%) and commercial inulin (0, 1, 2 and 3%) were used in synbiotic yogurt containing Lactobacillus acidophilus and Bifidobacterium lactis. The addition of commercial inulin and the extracted inulin powder increased acidity and consequently decreased pH. Adding commercial inulin to milk increased the viscosity and reduced the final product syneresis. The extracted inulin powder at low concentrations had a positive effect on these properties. By increasing storage time, the acidity and syneresis of the synbiotic yogurt increased and pH decreased. The presence of these compounds in milk had a positive effect on the viability of the probiotics bacteria in yogurt, which the effect of commercial inulin on the survival of probiotic bacteria being greater than that of the extracted inulin. Addition of commercial inulin had no significant effect on the color properties of the yogurt samples, while the addition of the extracted inulin powder significantly reduced the brightness index (L*) compared to the control sample and increased the redness (a*) and yellowness (b*) indexes. All sensory properties improved by increasing commercial inulin, whereas 1.5% of the extracted inulin powder had no negative effect on sensory properties of the synbiotic yogurt compared to control.