Utilization of inulin extracted from chicory (Cichorium intybus L.) roots to improve the properties of low-fat synbiotic yoghurt

Abstract

The present study was aimed to extract and purify inulin from chicory roots and evaluate the physicochemical properties and functional groups of the purified inulin for comparison with those of standard chicory inulin. This study investigated the impact of various inulin concentrations on of low-fat yoghurt quality, including physicochemical, microstructural, textural and sensory properties, the impact of inulin as a prebiotic on the growth and viability of synbiotic yoghurt. The characteristics of the microstructure were investigated by scanning electron microscopy (SEM). For functional group detection, Fourier transform infrared (FTIR) spectroscopy was used. For separate and quantify of inulin content determination were performed on a high-pressure liquid chromatography combined with refractive index detector (HPLC-RID) method. The evaluation of inulin extracted from chicory roots revealed a white powder with a natural taste and no off flavours. Inulin was less sweet than sugar (sucrose) and was moderately soluble in water, colourless, and clear to hazy, with a pH of 5.84. Chicory inulin showed a high content of reducing sugars (4.9%). The addition of inulin at 1% enhanced the microstructural, textural and sensory properties of yoghurt compared to those of the control, and this yoghurt can be considered a functional synbiotic product because it contains both probiotics (>6 log cfu g−1) and prebiotics. The inulin addition to the probiotic yoghurt improved the viability of S. thermophilus, L. bulgaricus, L. acidophilus and B. bifidum during storage. Overall, low-fat synbiotic yoghurt containing 1% inulin was comparable in its performance features to the full-fat probiotic yoghurt control.