# The Yeast-Based Robotic Encapsulation Scenario: A Systematic Review and Meta-Analysis
## 3 Results and Discussion  
### Study Inclusion  
The article search was carried out between June 2020 and February 2021, chronologically, both for surveying articles and for data collection and analysis. Initially, a survey was carried out for data collection on the Cochrane, LILACS, PubMed, Scielo, ScienceDirect, and TripDatabase platforms (Table 1). A total of 2058 citations were obtained considering the following keywords: \"Yeast + Probiotic + Microencapsulation\", \"Probiotic + Microencapsulation\", \"Probiotic + Encapsulation\", and \"_Saccharomyces_ + Probiotic + Microencapsulation\". ScienceDirect had the highest number of citations (n = 1888), followed by TripDatabase (n = 66). In both databases, the term \"Probiotic + encapsulation\" had the highest number of citations at 1180 and 37, respectively. The second term with the highest number of citations was \"Probiotic + microencapsulation\" with 537 and 26 observations in ScienceDirect and TripDatabase, respectively. In the articles survey and data collection, four stages were considered: identification; sorting; eligibility; and articles included in the analysis (Figure 1). The records identified through the search in the databases considered a total of 1269 articles with the researched theme. In the screening stage, one article was excluded because it was duplicated--that is, it was found on more than one platform--and 1247 were excluded because they were outside the theme and objective of the study. Subsequently, in the eligibility stage, the criteria for which were determined at the beginning of the research, seven articles were excluded for the following reasons: they addressed the use of lactic acid bacteria (LAB); yeasts were not microencapsulated/encapsulated; they used of some cell wall components as LAB encapsulation material; they evaluated the encapsulated yeast in relation to the effects on the organism's health, without describing the viability of the encapsulated probiotic itself; they conducted studies on animal models; their data centered around morphology, but additional media data were not provided to investigate microencapsulation efficiency; and the data obtained were related to the growth of fish, but did not present data related to its action, nor how its viability could be measured. Therefore, 14 complete articles, published in high-impact journals throughout the years 2013 to 2019 were selected for analysis, focused on in vitro assays with probiotic yeasts. In the referenced works, the spray drying (four times) and extrusion (four times) techniques were the most recurrent. Spray chilling and gelation techniques were reported only once each. The encapsulation technique was not directly related to the size of the microcapsule; that is, different patterns were observed in the same technique, with the smallest reported microcapsule measuring 3.31 \(\upmu\)m and the largest measuring 2960 \(\upmu\)m. However, as observed in Table 2, the largest capsule size values (1500 and 1700-2960 \(\upmu\)m) were obtained in the EX-technique. This pattern was not maintained in all studies, since, in two studies, the size ranged from 50 to 90 \(\upmu\)m.  
The microcapsule composition varied among the analyzed articles, with emphasis on seven ingredients (milk protein, starch, maltodextrin, gum arabic, xanthan gum, alginate, and chitosan) which appeared in more than one formulation. In some studies, more than one formulation of ingredients was used, reaching a total of five ingredients in the same formulation. The most common compounds among the formulations were as follows: alginate (sodium and calcium) and maltodextrin, which appear in eight and five formulations, respectively, alone or in combination. Alginate was cited as a component of the microcapsule in 6 studies and gum arabic in 4 of the 14 articles analyzed. In [38], four of the six most used ingredients in other studies (milk protein, starch, maltodextrin, and gum arabic) were used individually. In contrast, ref.