Microencapsulation of Lactobacillus casei in psyllium-gelatin gum enriched with selenium: effects on bacterial survival under gastrointestinal and storage conditions

The current study aimed to evaluate the viability of microencapsulated Lactobacillus casei to simulated gastrointestinal digestion and storage after optimisation of the psyllium (PG) and gelatin (GE) gum mixtures (2:1, 1:2, 1:1, 0:1 and 1:0) enriched with selenium (Se). Our results exhibited that the size of spherical particles ranged from 643.9 +/- 1.77 to 1151.5 +/- 3.38 mu m. The ratio of 2PG:1GE showed the highest encapsulation efficiency (89.8% +/- 0.77) and selenium entrapment (6.92 +/- 0.16 ppm). Fourier-transform infrared spectroscopy (FTIR) data exposed new spectra in the 2PG:1GE samples. Microencapsulated L. casei with 2PG:1GE were resistant to simulated gastric conditions (pH 1.8, 1 h) and bile solution (pH 7.4, 120 min), and during the storage period at room temperature, leading to significant (p < 0.05) higher survival in comparison with free cells. In short, this study optimised the concentrations of PG and GE to entrap Se and carry L. casei efficiently, providing significant protection during exposure to various aggressive conditions.