Solving the delivery of Lactococcus lactis: Improved survival and storage stability through the bioencapsulation with different carriers

Abstract

Probiotics are live microorganisms that confer beneficial effects on the health of the host if administered in adequate amounts (106 CFU viable microorganisms/g of food). As the most frequent route of administration of these microorganisms is oral, the number of them that remains viable through the gastrointestinal tract decreases substantially. Thus, in this research work, we developed a series of alginate-based microparticles using different adjuvants such as methylcellulose, carboxymethylcellulose, chitosan, carbopol, β-cyclodextrin, starch, carrageenan, and Eudragit® RS 100 as carriers for improving the survival of Lactococcus lactis. The alginate-based formulations exhibited very good drug encapsulation efficiency, up to 90%. Release studies from selected microparticles revealed that almost 100% of bacteria were in solution at 30 min. By scanning electron microscopy, irregular nonporous particles with a size between 200 and 500 µm were seen. In particular, microparticles formulated with alginate–carboxymethylcellulose and alginate–methylcellulose exhibited the best protection for the bacterial cells against both simulated gastric juice and simulated intestinal juice. In addition, those microparticulate systems were able to maintain the viability of the encapsulated bacteria in large numbers for at least 24 weeks. Thus, the present study confirmed that these alginate-based microparticles are a valuable approach for keeping the viability and storage stability of L. lactis.