Viability of Lactobacillus rhamnosus GG microencapsulated in alginate/chitosan hydrogel particles during storage and simulated gastrointestinal digestion: Role of chitosan molecular weight

Authors: RAO, JIAJIA - North Dakota State University; QI, XIAOXI - North Dakota State University; SIMSEK, SENAY - North Dakota State University; CHEN, BINGCAN - North Dakota State University; Ohm, Jae-Bom

Submitted to: Soft Matters
Publication Type: Peer Reviewed Journal
Publication Acceptance Date: 1/13/2020
Publication Date: 1/13/2020
Citation: Rao, J., Qi, X., Simsek, S., Chen, B., Ohm, J. 2020. Viability of Lactobacillus rhamnosus GG microencapsulated in alginate/chitosan hydrogel particles during storage and simulated gastrointestinal digestion: Role of chitosan molecular weight. Soft Matters. 16:1877-1887. https://doi.org/10.1039/C9SM02387A.
DOI: https://doi.org/10.1039/C9SM02387A

Interpretive Summary: Probiotics such as Lactobacillus rhamonsus GG (LGG) alleviate health problems in human beings. However, most of the probiotics easily lose their viability and potential health benefits during processing, storage and digestion. Sodium alginate hydrogels have received much interest as encapsulation material of probiotics to preserve their viability. Chitosan, which is a carbohydrate polymer, has high potential as a coating material to improve the properties of sodium hydrogel particles for encapsulation of probiotics. In this study, three kinds of chitosan: chitosan oligosaccharide, low molecular weight chitosan and medium molecular weight chitosan were investigated for their influence on sodium hydrogel particles in encapsulation of the probiotic, LGG. Specifically, this research investigated the effect of a chitosan coating on the survival of encapsulated LGG during long-term storage (95 days) at variable temperatures (37, 25, and 4 C) and simulated human digestion. The results demonstrated that the chitosan coating significantly enhanced the viability of the encapsulated LGG during storage. However, no improvement was found in simulated human digestion. This information will be valuable for the improvement of encapsulation of probiotics.

Technical Abstract: Chitosan coated sodium hydrogel particles with desirable physical properties is one of the promising means for probiotics encapsulation. It is, therefore, essential to understand the role of chitosan in such systems and to optimize the functional performance of particles for improving viability of probiotics. In this study, three kind of chitosan: chitosan oligosaccharide (COS), low molecular weight chitosan (LMW'chitosan) and medium molecular weight chitosan (MMW'chitosan) were applied to form a protective layer on alginate hydrogel particles through electrostatic interaction. Physical properties and morphology of the hydrogel particles were examined by Scanning Electron Microscopy, Fourier Transform Infrared spectroscopy and Textural Analyzer. The possible protective effect of chitosan coating formed by three kinds of chitosan on the survival of the encapsulated Lactobacillus rhamonsus GG during long-term storage (95 days) at variable temperatures (37, 25, and 4') and in simulated gastrointestinal conditions were investigated. The results demonstrated that the coated chitosan oligosaccharide on the alginate particles significantly enhanced the storage stability of encapsulated LGG. However, the improvement on the viability of encapsulated LGG by all three chitosan coatings in simulated digestion, as reported in previous studies, were not found in this research.