Viability of Lactobacillus rhamnosus GG microencapsulated in alginate/chitosan hydrogel particles during storage and simulated gastrointestinal digestion: Role of chitosan molecular weight
Sodium alginate hydrogel particles coated with cationic biopolymers has shown to be one of the promising means for probiotics encapsulation and protection. In this study, we aimed to systematically explore the effect of molecular weight of chitosan coating on the functional performance of sodium alginate hydrogel particles in improving viability of Lactobacillus rhamonsus GG (LGG). We first electrostatically deposited three different molecular weight of chitosan, i.e., chitosan oligosaccharide (COS), low molecular weight chitosan (LMW‒chitosan) and medium molecular weight chitosan (MMW‒chitosan) on sodium alginate hydrogel particles. Both SEM and FTIR results indicated that chitosan was successfully deposited to the surface of the hydrogel particles. We then evaluated the effect of chitosan MW on the viability of LGG encapsulated in the hydrogels during long-term storage and under simulated gastrointestinal digestion. Among them, the hydrogel particles coated with COS prevented the viability loss of LLG during long-term storage under different temperature (4, 25 and 37 °C). However, we did not found any improvement on the viability of encapsulated LGG by all three chitosan coatings in simulated digestion.