## 1 Introduction  
Yogurt is a type of coagulated milk product with smooth texture, and that has a gentle sour and pleasant flavor that results from lactic fermentation with _Lactobacillus delbrueckii_ ssp. _bulgaricus_ and _Streptococcus thermophilus_[1]. Yogurt is the best-known nutritional carrier for efficient transfer of beneficial microbes into the body [2]. Recently there is an intensified demand for a new range of dairy products, including symbiotic yogurt containing both probiotics and prebiotics [3, 4]. Probiotic lactic acid bacteria (LAB) have been shown to produce abundant bactericidal proteins in dairy foods [5, 6]. Synbiotic yogurt has become increasingly popular as a type of functional food that beneficially affect the health condition of human beings [7; 8]. Probiotics are live microbes that confer a health benefit for the host when introduced in a suitable amount [9]. Probiotic microorganisms are generally required to survive at body temperature and be resistant to stomach acid and bile salt [7]. Native bacteria are not probiotics unless they are isolated, purified, and proved beneficial to health when introduced. Prebiotics are a non-digestible part of food, which may serve as nutritional supplements for probiotic microorganisms to enhance their survival chances and implantation in the host intestinal tract [10]. Thus, prebiotics cause particular changes in both the composition and activity of the gastrointestinal microflora that confer benefits to the host well-being and health [11]. Probiotics may provide a potentially promising approach to preventing microbial dysbiosis [12]. However, synbiotics could better influence lipid profiles and protect against colorectal cancer than probiotics or prebiotics alone [13]. _Saccharomyces boulardii_ CNCM I-745 was previously identified as a unique species of yeast characterized as a probiotic strain among a few probiotic yeasts reported to date [14]. Unlike other _Saccharomyces_ strains with optimal growth at about 30 \({}^{\circ}\)C, _S. boulardii_ survived best at 37 \({}^{\circ}\)C, which was advantageous as one of the few yeasts that did best at human body temperature [15]. _S. boulardii_ was considered as a safe microorganism with non-toxic and non-pathogenic effects, and it could be implanted in large quantity in the gastrointestinal tract maintaining constant level of viability [16]. A bio-therapeutic agent based on the use of _S. boulardii_ was developed by oral administration of this probiotic strain to treat recurrent _Clostridium difficile_-associated disease [17]. Inulin, one of the most common prebiotics, is mainly found in roots of chicory (_Cichorium intybus_), garlic (_Allium sativum_), wheat (_Triticum_ spp. ), oat (_Avena sativa_) and dalia [18]. It is known to be a storage polymer consisting of a \(\beta\)-2-1-linked fructosyl unit with a terminal glucosyl unit [19]. Currently, there is an increasing interest in addition of inulin and other oligofructose to food products (e.g., yogurt) for their healthful effects (e.g., enhancing _Lactobacillus_ and _Bifidobacterium_ growth in the colon, boosting bioavailability of a variety of minerals like calcium and iron, increasing antioxidant activities, and boosting immune functions) [20]. Inulin and oligofructose were shown to improve sensory quality and increase the probiotic viable count in functional dairy foods [21]. Supplementation of food fibers such as inulin could reduce wheying-off and thus improve the textural properties of food matrix, and it was also found to remarkably elevate viscosity and shear thinning behavior of different dairy products [22]. The present study was designed to develop symbiotic yogurt by using probiotic _S. boulardii_ CNCM I-745 and prebiotic inulin for potential application in the dairy industry.