## 3 Results and Discussion
Effect of Spray Drying on the Survival of L. plantarum and Strains of the Genus Bifidobacterium and Viability during Storage  
The operating conditions (0.6% w/v of CM at 90 \({}^{\circ}\)C) that maximize the survival of _L. rhamn_ were applied for encapsulating _L. plantarum_, _B. infants_, and _B. longum_ (probiotic bacteria commonly found in the human gastrointestinal tract and present in many dairy products and functional foods). Cell damage and activity loss may occur during processing, and also during storage of the dehydrated cells. Thus, the encapsulation process should ensure that the microorganisms survive processing, as well as maintain their viability during storage. In this context, viability during storage at 4 and 25 \({}^{\circ}\)C was evaluated for 60 days. The survival of different probiotic bacteria after drying (Table 5) was greater than 90% (_L. rhamn_s, 91.23%; _L. plantarum_, 94.77%; _B. longum_, 96.07%; and _B. infants_, 97.24%). The high probiotic bacteria survival suggests that CM thermoprotected cell inactivation during spray drying, avoiding damage to the membrane, ribosome, DNA, and protein [33; 34]. On the other hand, the fiber (2.35%) content of CM may offer different degrees of protection to the cell and act as a gelling agent, increasing encapsulating efficiency and microcapsule stability. Other factors that could also explain this high survival are strain growth phase (late-log phase or start-stationary phase) during spray drying and the intrinsic tolerance of strains to heat. In this study, probiotic bacteria were harvested in the late-log phase, the stage in which spray drying causes low cell damage, and a high number of viable cells is obtained after drying. [PERSON] et al. [66] determined that stationary phase cultures were more resistant to heat than exponential phase cultures, while [PERSON] et al. [26] determined that the stationary phase was most suitable for microencapsulation by spray drying. Moreover, the survival of the _Bifidobacterium_ species after spray drying is dependent on the kinds of carrier [67] and varies with the strains because some have a distinctive tolerance to heat [54]. In this assay, the moisture content of powders varied between 2.95 and 5.77% (Table 4), values that ensure the fluidity and stability of the product and avoid its agglomeration [65]. All spray-dried microcapsules containing probiotic bacteria show high viability for a period of 60 days of storage at 4 \({}^{\circ}\)C (Figure 3). The initial counts of probiotics varied between \(10.50\pm 0.10\) and \(9.64\pm 0.08\) log CFU/g for _B. infants_ and _L. rhamn_s, respectively. Then, after 60 days of storage, the counts varied between \(10.04\pm 0.13\) and \(8.46\pm 0.25\) log CFU/g, for the same probiotic strains, values above the recommended levels for probiotic food throughout the storage time, i.e., equal to or greater than 6 log CFU/g of the product [20; 68]. In addition, the viability of microcapsules containing _L. plantarum_, _B. infants_, or _B. longum_, stored after 60 days at 4 \({}^{\circ}\)C (Figure 3a), was significantly (\(p<0.05\)) greater than the viability of _L. rhamn_s. The high viability values obtained for all probiotic bacteria can be explained by a decrease in their metabolic activity when stored at refrigeration temperatures. On the other hand, during storage of the microcapsules at 25 \({}^{\circ}\)C, a continuous decrease was noted in the viability of the four probiotics (Figure 3b). The initial counts of probiotics varied between \(10.24\pm 0.31\) and \(9.45\pm 0.17\) log CFU/g for _B. infants_ and _L. plantarum_, respectively. However, _L. rhamn_s lost