## 2 Materials and Methods
### Emulsions Characterization and Preparation  
In this study, dispersion of _Lbs. rhamn_s GG was prepared as multicomponent aqueous emulsion based on starch Capsul(r) HS, whey protein concentrate (WPC 80%), soy lecithin, vitamin C, and various oils, which were fed as liquid emulsion into the spray drying system to obtain microcapsules in form of dry powder.  
Starch is widely available as a low-cost food product. The modified starches are widely used as encapsulating agents due to their unique properties such as stabilization of the emulsion, low viscosity of formed solutions, and film-forming capabilities [28]. Whey protein concentrates (35\(-\)85% protein) and whey protein isolates (of purity >95% wt. protein) have been used as encapsulating materials of probiotic bacteria [29]. Whey proteins are a suitable medium for encapsulation of bacteria due to their high nutritional composition and good film-forming capabilities. They also have an amphoteric character, good thermal stability, proper gelling, capabilities of both fast hydration/dehydration, and good emulsifying properties. Furthermore, they can interact, trap, and protect probiotic ingredients [30]. Soy lecithin is an amphiphilic substance with both lipophilic and hydrophilic properties that can be used to cover the surface of powder particles, constituting an interaction between the fatty substance and water, thanks to which the dispersion of the product in an aqueous environment is easier and final system is more stable [31]. Lipid matrices such as fatty acids, mono- and diglycerides, vegetable oils, waxes, and resins are used to encapsulate hydrophilic probiotics to protect them against water and moisture [32; 33].  
Since lipids have poor mechanical properties and are chemically unstable, they are often combined with other biopolymers such as polysaccharides or proteins to increase their efficiency in the encapsulation of probiotics [34].  
In addition, oily substances have the advantage that they can only be digested by the lipase in the intestine so that the bacteria can be released close to their optimal site of action [26].  
Fifteen percent (w/v) of aqueous starch solution was sterilized in the autoclave at 121 \({}^{\circ}\)C for 15 min (Prestige Medical, Blackburn, UK), and after cooling down, an additional 5% wt. aqueous WPC was added while stirring on a magnetic stirrer (IKA, Warsaw, Poland) in the appropriate amount to obtain the final 20% (w/v) solution. Afterwards, lecithin and ascorbic acid were added in a ratio of 1:10 at a final concentration of 0.6% wt. to oil concentration, and pH was adjusted to 6.5 with 1 M NaOH. The bacterial biomass was dispersed in appropriate oil while stirring at 300 rpm using a magnetic stirrer (IKA) and then was added to aqueous starch, WPC, soy lecithin, and ascorbic acid solution in the appropriate amount to obtain 10\({}^{9}\) CFU/mL and stirred at 300 rpm.  
Subsequently, all the formed emulsions were spray-dried. Oils were applied in two different concentrations of 20% and 30% wt. to the dry mass of starting dispersion. A solution of starch, whey protein concentrate, lecithin, and ascorbic acid without oils was used as a control.