Enhancement of the Viability of Lactobacillus rhamnosus GG Using Bambara Groundnut Protein Isolate/Alginate with Inulin as Encapsulating Materials by Complex Coacervation Technique: A Response Surface Methodology Approach
Microencapsulation is widely used to stabilize probiotics to allow their full functioning. The aim of the study was to determine the optimal combination of Bambara groundnut protein isolate (BGPI)/alginate and inulin as the encapsulating agents for the probiotic; L a c t o b a c ill u s r h a m n o s u s GG was established using response surface methodology (RSM). The probiotic cells were encapsulated in various ratios of BGPI/alginate-inulin wall according to RSM with complex coacervation technique. It was found that the optimal concentration level of 1:1 weight ratio BGPI/alginate solution was 2.14% w/v with 3.23% w/v inulin. The formulation yielded 96.64% encapsulation efficiency, having survival rate as high as 95.76% and 94.48% after freeze drying process and after exposure to acid condition respectively. Not only was the validity of the in-use predicted model confirmed but capsules also improved the survival rate of the cells in simulated gastric fluid (SGF) by ∼ 4.88 log CFU/ml after 3 h compared with free cells and demonstrated the cell release of 8.53 log CFU/ml within 4 h. The survival rate of entrapped cells stored at 4°C and 30°C for 6 months (7.82 log × FU/ml and 8 log CFU/ml, respectively) were superior to those of free cells in the identical conditions, (4.10 log CFU/ml and <1 log CFU/ml respectively). Encapsulation of probiotics in BGPI/alginate-inulin capsules offers opportunities for improving the viability of cells during freeze drying process, exposure to the acidic medium of the stomach and storage.
Sanae Kaewnopparat*, Kanyanat Kaewiad, Nattha Kaewnopparat and Damrongsak Faroongsarng.