Sodium alginate microcapsules co-encapsulated with chitosan hydrochloride as an alternative to increase the viability of Lactobacillus rhamnosus

Over the years, the population has shown a growing demand for foods that, in addition to nutritional benefits, have additional properties, such as those enriched by probiotic microorganisms, especially the Lactobacillus rhamnosus species. However, this microorganism in its free form may be susceptible to a decline in cell viability during storage and passage through the gastrointestinal tract. One form of protection is microencapsulation with biodegradable polymers such as sodium alginate, through techniques such as ionic gelation by extrusion using vibration technology. In addition, an additional alternative for probiotic protection is co-encapsulation with chitosan hydrochloride. Thus, this work sought to develop and characterize microcapsules of calcium alginate (MA) coated with chitosan hydrochloride (MACQ) as an additional alternative for the protection Lactobacillus rhamnosus isolated from a kefir sample.The capsules were prepared using Bucchi's B-395 Pro encapsulator, the percentage of encapsulation was calculated, and viability was evaluated for 60 days in refrigerated storage (7+1ºC) and characterized by optical microscopy and Scanning Electron Microscopy (SEM). The results revealed a high encapsulation efficiency of 92.22% for MA, 94.54% for MACQ. Microencapsulation provided greater protection to the probiotic strain coated with chitosan hydrochloride (~1.13 log CFU/mL reductions) during 60-day storage at 7°C compared to free cells (3.37 log CFU/mL reductions). The microparticles were evaluated by optical microscopy and were intact, dispersed without agglomeration, and spherical. Scanning electron microscopy showed that the chitosan coating made the alginate microparticle structure less porous and more stable. These findings show that microencapsulation in an alginate matrix associated with coating with chitosan hydrochloride may be a more effective methodology to preserve the viability of probiotics.