Microencapsulation of Lactobacillus plantarum (MTCC 5422) with fructooligosaccharide as wall material by spray drying

Microencapsulation is a promising technique for delivery of live microbial supplements through foods. Prebiotics like ‘fructooligosaccharide (FOS)’ can be used as a wall material to produce synbiotics. However, the low glass transition temperature (Tg) of FOS causes stickiness when used as wall material during spray drying. This problem was alleviated by FOS in combination with whey protein isolate (WPI) or denatured whey protein isolate (DWPI) for encapsulating the probiotic bacteria Lactobacillus plantarum (MTCC 5422). Microencapsulation was performed with wall materials FOS, FOS + WPI, FOS + DWPI at two different core-to-wall ratios of 1:1 and 1:1.5. FOS + WPI and FOS + DWPI microcapsules of 1:1 core-to-wall ratio exhibited higher encapsulation efficiency, lower residual moisture content and narrow range of particle size distribution than 1:1.5. However, microcapsules of 1:1.5 core-to-wall ratios enhanced the storage stability and tolerance of probiotic cells in the simulated gastric and intestinal conditions. FTIR analysis confirmed the presence of whey proteins and FOS in the microcapsules after spray drying. On overall comparison, FOS + DWPI microcapsules of 1:1 core-to-wall ratio had higher encapsulation efficiency (98.63%) but 1:1.5 ratio exhibited better storage stability and protection in simulated gastric, as well as intestinal condition than the other encapsulates.