Enhancing encapsulation efficiency of alginate capsules containing lactic acid bacteria by using different divalent cross-linkers sources

Despite the fact that probiotic encapsulation in cross-linked alginate capsules is widely studied and applied, there is still not enough research knowledge on the cross-linkers' effect and also the encapsulation process still needs to be optimized in order to reduce the mortality of the cells during gelation. Thus, the aim of this study was to investigate the toxic effect on the viability of Lactobacillus plantarum F1, Lactobacillus reuteri 182 and Lactobacillus helveticus 305, caused by: calcium chloride, calcium carbonate, calcium lactate and calcium edetate and rarely used strontium chloride, by providing a microbial growth dynamics. Further, the capsules, produced by using three different encapsulation methods, were compared through the evaluation of encapsulation efficiency were compared. The results showed that CaCl2 caused the highest mortality of the cells when the capsules were made by extrusion method. The toxic CaCl2 effect was also approved by measuring bacterial growth. The highest encapsulation efficiency of all the tested strains was reached when the capsules were made using calcium lactate via extrusion and emulsification/external gelation methods. The encapsulation efficiency in the capsules made via emulsification/internal gelation was similar for both tested cross-linkers sources - calcium carbonate and calcium edetate. What is more, research revealed that the most sensitive to toxic effect of cross-linkers was L. helveticus.