## 3 Results and Discussion
### Release Kinetics  
The release of encapsulated _S. thermophilus_ TH982 after incubation in simulated intestinal fluid was evaluated after 30, 60, 90, 120, 150, and 180 min, as reported in Figure 4. After 30 min of agitation at 100 rpm at 37 \({}^{\circ}\)C in 50 mM K\({}_{2}\)HPO\({}_{4}\), a great release of cells encapsulated with S + F was detected. Considering the initial number of cells entrapped in this type of capsules (9.73 \(\pm\) 0.04 log CFU/g of capsules), the number of cells released in the simulated intestinal fluid after 30 min was 8.83 \(\pm\) 0.04 log CFU/mL of K\({}_{2}\)HPO\({}_{4}\), representing a very high value compared with the other types of encapsulating matrices after 180 min, which resulted about 2-log lower. This result confirms what was visible during the experiment: after 30 min, there was an evident solubilization of S + F capsules, a characteristic not displayed by the others (S, S + I, and S + G). Moreover, the number of released cells suggests that once liberated, _S. thermophilus_ TH982 can withstand well simulated intestinal conditions, since after 180 min the number of cells released from S + F capsules was 9.72 \(\pm\) 0.05 log CFU/mL, which means 99.89% of the initial entrapped cells. It is essential to ensure that the capsules give protection through the simulated gastrointestinal passage and ensure that the encapsulation matrix allows a release of viable and metabolically active cells in the intestine [30,43]. The release of the cells from microcapsules in the colon is essential for the growth and possible colonization of probiotics [30,44]. In the absence of this property, the entrapped organisms and the capsules will be washed out from the body without exerting a significant beneficial effect [45]. Many studies investigated the release of encapsulated probiotics in simulated intestinal fluid; however, to the best of our knowledge, there is no similar outcome from any encapsulating agent reported in the literature to date [25,30,43]. [PERSON] et al. [45] reported the release of encapsulated _L. acidophilus_ in alginate-starch microspheres using a simulated colonic fluid with the same formulation (50 mM KH\({}_{2}\)PO\({}_{4}\), pH 7.4 \(\pm\) 0.2 during 2.5 h). They found that the cell count after 150 min of incubation was 7.45 log CFU/mL, suggesting that all the microencapsulated cells were released at that time (initial number of 7.47 log CFU/g of capsule). Although 150 min is about the time needed for intestinal transit of microcapsules, they did not find a significant release after 30 min [45]. In another study, a fully released _L. plantarum_ encapsulated with sodium alginate and sodium alginate with inulin in a 60-min exposure to simulated intestinal fluid was reported. From the results, it was concluded that the release mechanism was probably due to the replacing of calcium ions in the encapsulation matrices. Also,  
Figure 4: Release kinetics of entrapped _S. thermophilus_ TH982 cells from different capsule formulations during incubation in a simulated intestinal environment. capsules with inulin showed a faster release rate during the first 20 min, which could have been induced by the addition of inulin in sodium alginate affecting the binding of calcium ion [33]. A possible mechanism that could be involved in the fast release of _S. thermophilus_ TH982 cells encapsulated with sodium alginate and 2\({}^{\prime}\)-fucosyllactose could be that this small soluble milk glycan used as a co-encapsulating agent in this experiment is formed by fucose linked to the two positions of \(\beta\)-Gal residues of lactose; hence no electrostatic repulsions may occur with the negatively charged carboxyl groups of sodium alginate structure. Therefore, the complete release of the cells is probably due to the vigorous interaction of the prebiotic structure with the divalent cations (Ca\({}^{2+}\)) of the sodium alginate network, resulting in disintegration of the \"egg-box\" structure in K\({}_{2}\)HPO\({}_{4}\).