Characteristics of Lactobacillus casei probiotic microparticles in L‑type methacrylic acid copolymer matrix

Lactobacillus casei (LC) is a type of lactic acid bacterium that is known for its beneficial probiotic properties. However, it is not typically found in the human intestine because it lacks acid resistance. LC thrives in an optimal pH environment of 6.8 and can be initiated in a more acidic environment at a pH of 3.5. This study purposed to compare the effect of L‑type methacrylic acid copolymer (MAC) as a matrix (0.50%, 0.75%, and 1.00%) on the physical characteristics of LC probiotic microparticles made by the spray drying process. Probiotic microparticles were also made from a dry suspension of LC FNCC 0090 bacteria and dispersed in a solution of L‑type MAC. The results showed that a rise in matrix content by 1.00% increased particle size (4.47 ± 0.19 µm) and reduced moisture content (7.45 ± 0.11%). The analysis of microparticle morphology also indicated a positive correlation between the level of L‑type MAC and the production of smooth, nonporous, and almost spherical shapes. In addition, it was observed that encapsulation efficiency (92.46 ± 0.17%) and protection against stomach acid (98.17% ±1.17%) increased with the level of the matrix.