# The Yeast-Based Robotic Encapsulation Scenario: A Systematic Review and Meta-Analysis
## 1 Introduction  
The food industry's development, awareness of the importance of diet in disease prevention, and improvements in nutritional science have led to a better understanding of the beneficial effects of foods and food ingredients on overall human health andwell-being [1; 2; 3; 4]. Thus, probiotics have gained prominence in food research. The World Gastroenterology Organization (2020) defines probiotics as \"live microorganisms which, when administered in adequate amounts, confer a health benefit on the host\". For a microorganism to be considered a probiotic, it must be safe for the host, resistant to gastric acidity and pancreatic secretions, able to adhere to the epithelium, and it must present antimicrobial activity, resistance to antibiotics, tolerance to food additives, and stability in the food matrix.  
Several studies have already shown that probiotics can reduce the development of cancer cells, decrease the occurrence of dysentery in patients with lactose intolerance, and promote immune improvement and nutrient absorption [5; 6; 7; 8; 9]. Recognized as promoters of health and well-being, probiotics are also able to stimulate the digestive system, increasing digestion capacity and helping in weight loss, as well as presenting beneficial effects on the cardiovascular systems, the bones, the brain, and the nervous system by restoring the intestinal flora [4; 8; 10; 11; 12; 13].  
The most studied probiotics so far have been _Lactobacillus_ spp. (9000 articles, 1265 of which from clinical trials), _Bifidobacterium_ spp. (625 clinical trials), Streptococcus (180 clinical trials), _Bacillus_ (110 clinical trials), and _Saccharomyces_ spp. (100 clinical trials) [4; 14]. The referred data show that the literature on probiotics of bacterial origin is extensive. However, studies on yeasts as probiotics are still scarce.  
The genus _Saccharomyces_ (yeast) is the most studied, with the two most used being _S. bouldari_ in humans and _S. cerevisiae_ in veterinary medicine [15; 16; 17; 18; 19]. One of the biggest challenges for the food industry is the incorporation of these probiotics into food products, maintaining their properties both in the processing stages and in the gastrointestinal tract [8; 20; 21; 22]. The beneficial effects of probiotics are directly dependent on a minimum number of living cells remaining viable when exposed to different types of pH in the stomach and intestine, to digestive enzymes, and to possible metabolic degradation during the digestive process [23; 24; 25; 26; 27; 28].  
To avoid the loss of probiotic viability, the development of methods that allow the survival of these cells to increase, especially when exposed to an adverse environment, was encouraged. Faced with this challenge, the encapsulation process has emerged as one of the most efficient technologies for protecting living cells [28; 29; 30; 31]. There are several techniques that can be used in the probiotic encapsulation process, and the most used methods are spray drying, spray chilling, spray coating, gelation, and extrusion [30; 32; 33].  
Given the importance of probiotic encapsulation methods, this work seeks to review yeast encapsulation techniques, as well as the main components used for encapsulation and their advantages. In addition, the effect of the encapsulated probiotic will also be analyzed.