Effect of Alginate-Microencapsulated Hydrogels on the Survival of Lactobacillus rhamnosus under Simulated Gastrointestinal Conditions

Abstract

Thanks to the beneficial properties of probiotic bacteria, there exists an immense demand for their consumption in probiotic foods worldwide. Nevertheless, it is difficult to retain a high number of viable cells in probiotic food products during their storage and gastrointestinal transit. Microencapsulation of probiotic bacteria is an effective way of enhancing probiotic viability by limiting cell exposure to extreme conditions via the gastrointestinal tract before releasing them into the colon. This research aims to develop a new coating material system of microencapsulation to protect probiotic cells from adverse environmental conditions and improve their recovery rates. Hence, Lactobacillus rhamnosus was encapsulated with emulsion/internal gelation techniques in a calcium chloride solution. Alginate–probiotic microbeads were coated with xanthan gum, gum acacia, sodium caseinate, chitosan, starch, and carrageenan to produce various types of microcapsules. The alginate+xanthan microcapsules exhibited the highest encapsulation efficiency (95.13 ± 0.44%); they were simulated in gastric and intestinal juices at pH 3 during 1, 2, and 3 h incubations at 37 °C. The research findings showed a remarkable improvement in the survival rate of microencapsulated probiotics under simulated gastric conditions of up to 83.6 ± 0.89%. The morphology, size, and shape of the microcapsules were analyzed using a scanning electron microscope. For the protection of probiotic bacteria under simulated intestinal conditions; alginate microbeads coated with xanthan gum played an important role, and exhibited a survival rate of 87.3 ± 0.79%, which was around 38% higher than that of the free cells (49.4 ± 06%). Our research findings indicated that alginate+xanthan gum microcapsules have a significant potential to deliver large numbers of probiotic cells to the intestines, where cells can be released and colonized for the consumer’s benefit.