## 1 Introduction  
The social awareness of the role of a properly balanced diet in maintaining good health has increased the demand for functional food that has an additional, beneficial effect on the specific functions of the human body [1]. Food products containing probiotic microorganisms are considered part of functional foods due to their health-promoting abilities. According to the Food and Agriculture Organization of the United Nation (FAO) and the World Health Organization (WHO), probiotic bacteria are living microorganisms that confer health benefits when consumed in adequate amounts only if their viability is well preserved (10\({}^{6}\)-10\({}^{7}\) CFU/g) [2]. Probiotics may consist of one strain or a mixture of few strains. The most commercially applied probiotic bacteria are bacteria of the genus _Lacticaseibacillus_ (_Lbs. casei_, _Lbs. rammaesi_, _Lbs. rammaosus_), _Lactobacillus_ (_Lb. acidophilus_, _Lb. gasseri_, _Lb. jolnsonii_) _Bifidobacterium_ (_B. bifidum_, _B. breve_, _B. longum_, _B. lactis_) and _Lactococcus_ (_L. lactis_) [3, 4, 5]. Probiotic bacteria play an important role in the host organism, among others: increase the population of beneficial bacteria in the intestines, fight pathogens, inactivate bacterial toxins, prevent infections of the genitourinary system, affect the immunity to intestinal diseases, reduce the side effects of antibiotics, lowering the level of cholesterol in the blood and have also an impact on reducing lactose intolerance and other food allergies [6]. However, in most cases, probiotic bacteria are sensitive to environmental conditions such as type of gas environment, pH, humidity, temperature, and light. When these conditions are not properly controlled, their viability decreases during both processing and storage, which reduces their effectiveness. In addition, losses in the number of viable microorganisms also occur during transport through the digestive tract, where they encounter particularly unfavorable conditions, such as a drastic change in pH [7; 8]. The viability and stability of probiotic bacteria pose technological and marketing challenges for industrial producers. Intensive research activities focus on the protection of probiotic microorganisms [3]. Encapsulation technologies were developed and applied successfully to protect probiotic bacteria from damage caused by external factors [9]. Microencapsulation refers to a process where bioactive ingredients or cells are surrounded/encapsulated by a protective continuous film of wall material [10]. Controlled release from microcapsules can occur due to changes in specific triggers such as pH, temperature, mechanical stress, and/or salt concentration [11]. This depends on both the type of encapsulation process and the applied protective substances [12]. The material inside the microcapsule (protected material) is called the core, active substance, filler, or inner phase. The material surrounding the core is defined as the wall, film-forming material, shell, membrane, matrix, or outer phase [13]. To microencapsulate probiotic bacteria are commonly used extrusion, emulsion, lyophilization, and spray drying techniques. Spray drying is one of the most frequently applied methods to encapsulate probiotics [14]. Its first observation and process description is dated to 1860 and the first simplified spray dryer device was patented by [PERSON] in the United States in 1872. Until 1920, the process wasn't used commercially in the production of powdered milk and detergents. Large-scale production of these products began in the eighties of the last century [15]. Spray drying is the dynamic phase transformation process of starting a system in a liquid state (emulsion, dispersion, solution) into a solid powder by spraying the feed into a hot drying gas [16]. This process takes place in four stages: atomization of the liquid into the form of fine droplets similar to a mist (1), contact of the resulting droplets with hot air (2), evaporation of water (3), and separation of the powder from the moist air stream (4) [14].