###### Abstract  
_Streptococcus thermophilus_ is widely used in dairy fermentation as a starter culture for yogurt and cheese production. Many strains are endowed with potential probiotic properties; however, since they might not survive in adequate amounts after transit through the human gastrointestinal tract, it is advisable to improve cell survivability during this passage. The present study evaluates the use of 2\({}^{\prime}\)-fucosyllactose, a prebiotic molecule from human milk, compared with other known molecules, such as gelatin and inulin, to form alginate-based microcapsules to fulfill these requirements. Such microcapsules, obtained by the extrusion technique, were evaluated in terms of encapsulation efficiency, storage stability, gastrointestinal condition resistance, and cell release kinetics. Results reveal that microcapsules made using 2\({}^{\prime}\)-fucosyllactose and those with inulin resulted in the most efficient structure to protect _S. thermophilus_ strain TH982 under simulated gastrointestinal conditions (less than 0.45 log CFU/g decrease for both agents). In addition, a prompt and abundant release of encapsulated cells was detected after only 30 min from microcapsules made with sodium alginate plus 2\({}^{\prime}\)-fucosyllactose in simulated gastrointestinal fluid (more than 90% of the cells). These encouraging results represent the first report on the effects of 2\({}^{\prime}\)-fucosyllactose used as a co-encapsulating agent.  
microencapsulation; probiotic; prebiotic; _Streptococcus thermophilus_ TH982; 2\({}^{\prime}\)-fucosyllactose 10.390/app11135761  
Academic Editors: [PERSON] and [PERSON]  
Received: 29 April 2021  
Accepted: 18 June 2021  
Published: 22 June 2021  
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**Subject**: **Thesiscentrifugal extrusion, encapsulation by a rapid expansion of supercritical fluid (RESS), freeze- or vacuum drying, and nanotechnological approaches [11]. The use of extrusion technology has many advantages for the encapsulation of probiotic cells. It is a simple and inexpensive method using mild operations, and the procedure does not involve any harmful solvent. Moreover, this technique appears to promote probiotic cell viability [12; 13; 14; 15].  
Combining alginate with some prebiotic molecules can also enhance cell protection in food systems [10]. Prebiotics form three-dimensional microcrystal networks that interact together, forming small aggregates that contribute to the better protection of the cells [16]. The most frequently used prebiotics in co-encapsulation are oligosaccharides, inulin, and resistant starches [16].  
2'-fucosyllactose (2'-FL), is a neutral trisaccharide composed of L-fucose, D-galactose, and D-glucose and is the most abundant oligosaccharides in human milk (HMO), accounting for about 30% of all of HMOs, i.e., 2-3 g/L [17]. This prebiotic molecule has been reported to display numerous health advantages in humans [18; 19; 20]. Another attractive characteristic of 2'-FL is its simplicity, which facilitates its de novo synthesis using microbial, enzymatic, or chemical methods [21].  
In this study, we aimed at evaluating the protective effect of 2'-FL on _S. thermophilus_ TH982 cells, a potential probiotic with the ability to produce high levels of folate [22] compared to some other common co-encapsulating materials in alginate beads.