Encapsulation of Lactobacillus acidophilus PTCC 1643 with composite wall of xanthan gum, soy protein isolate and fructooligosaccharide: investigation microcapsule characteristics

Encapsulation is an effective method to increase the viability of probiotic bacteria. The aim of this research is to determine the optimal formulation for microencapsulation of Lactobacillus acidophilus PTCC 1643 with soy protein isolate, xanthan gum and fructooligosaccharide as wall materials by freeze drying method. For this purpose, 19 treatments with Combine design were prepared by Design expert software. Encapsulation efficiency, particle size, zeta potential, and probiotic viability, FTIR and SEM tests were performed on the samples. The optimal sample was selected based on the lowest zeta potential and particle size, and the characteristics of microcapsules were determined by the aforementioned tests. The results showed that probiotic viability increased and decreased with increasing concentration of soy protein isolate and xanthan gum, respectively. The particle size of the samples also increased with increasing the concentration of soy protein isolate. In general, according to the protective effect of xanthan gum, soy protein isolate and fructooligosaccharide on probiotics, it can be concluded that these compounds can be used as a wall for coating to enrich food products.