Effect of encapsulation of Lactobacillus reuteri (ATCC 23272) in sodium alginate and tomato seed mucilage on properties of ketchup sauce

In the current work, encapsulation of Lactobacillus reuteri (LR) by double-layer extrusion was investigated. The microencapsulated (bead) wall was prepared with sodium alginate and tomato seed mucilage (TSM) in different concentrations (0.2, 0.4, 0.6, and 0.8 %) as a first and second layer, respectively. The encapsulation efficiency (EE), survival at 72 °C, and cold storage were assessed in beads. The viscosity, acidity, pH, the survivability of LR in simulated gastrointestinal condition (GI), storage time were measured in ketchup sauce. The results showed that EE was 91.54 % for 0.8 % sample. In heat stress conditions, MLR showed a higher survival rate (52.8 %) than FLR (not detected after 4 min). Following the 28th day of cold storage, the survival of the MLR sample (54.08 %) remained higher than the FLR (42.37 %). In ketchup sauce, the survival rates were 57.37 and 51.61 % for MLR and FLR, respectively. In the GI simulating condition, the final survival rates of MLR and FLR samples were 54.93 % and 48.26 %, respectively. The MLR had the more significant value in viscosity (72,864 mPa s⁻¹), and acidity (4 g.100 g⁻¹) but pH was equal among the samples. Therefore, applying alginate and TSM can protect LR from harsh environmental conditions and in ketchup sauce.