Survival of probiotic bacteria nanoencapsulated within biopolymers in a simulated gastrointestinal model

The objective of this work was to fabricate electrospun nanofiber mats (nano-scale in diameter) using a combination of corn starch (CS) and sodium alginate (SA) and encapsulate probiotic strains of lactobacilli (Lactobacillus acidophilus (LA5) and Lactobacillus rhamnosus 23,527 LGG) and bifidobacteria (Bifidobacterium bifidum and Bifidobacterium animalis) to improve their survival in simulated gastrointestinal fluids. The viability of the lactobacilli and bifidobacteria (determined using plate count method) after electrospinning was 94.1% and 89.4% of the initial population. Upon exposure to in vitro condition of gastric fluid (HCl and pepsin, at 37 °C), the population (starting level of 9 log CFU/mL) of nanoencapsulated lactobacilli and bifidobacteria decreased only by 1.58 and 1.03 log CFU at 120 min. Treated with in vitro prepared intestinal fluid (dipotassium hydrogen phosphate, sodium hydroxide, bovine bile salt, and trypsin) no cell was detected at 30 min and the number of coated lactobacilli and bifidobacteria decreased by 2.90 and 2.23 log CFU at 120 min in comparison to nonencapsulated control. After 180-min exposure to simulated gastrointestinal fluid, population of encapsulated lactobacilli and bifidobacteria decreased by 3.02 and 2.55 log CFU at 180 min. The viability of the probiotic bacteria in simulated gastrointestinal conditions was enhanced significantly (81–100% of the initial population) by nanoencapsulation within nanofiber mats of CS/SA.