Microencapsulation of alginate-immobilized bagasse with Lactobacillus rhamnosus NRRL 442: Enhancement of survivability and thermotolerance

• Probiotic immobilization before microencapsulation significantly enhanced microencapsulation efficiency and cell survivability.
• The high efficiency was achieved even with the usage as low as 1% NaA concentration.
• Increasing the ratio of NaA:SB significantly increases the cell survivability after microencapsulation and heat exposure.
• Dense structure of alginate-SB matrices provides better heat protection.
• We successfully synthesis the lethal heat resistant microcapsules of alginate-immobilized L. rhamnosus on SB.

The aim of this research was to enhance the survivability of Lactobacillus rhamnosus NRRL 442 against heat exposure via a combination of immobilization and microencapsulation processes using sugarcane bagasse (SB) and sodium alginate (NaA), respectively. The microcapsules were synthesized using different alginate concentration of 1, 2 and 3% and NaA:SB ratio of 1:0, 1:1 and 1:1.5. This beneficial step of probiotic immobilization before microencapsulation significantly enhanced microencapsulation efficiency and cell survivability after heat exposure of 90 °C for 30 s. Interestingly, the microcapsule of SB-immobilized probiotic could obtain protection from heat using microencapsulation of NaA concentration as low as 1%. SEM images illustrated the incorporation of immobilized L. rhamnosus within alginate matrices and its changes after heat exposure. FTIR spectra confirmed the change in functional bonding in the presence of sugarcane bagasse, probiotic and alginate. The results demonstrated a great potential in the synthesis of heat resistant microcapsules for probiotic.