The Influence of Microencapsulation with a Modified Chitosan (Water Soluble) on β-Galactosidase Activity

The aim of this work was to investigate the possibility of producing microparticles containing beta-galactosidase, using a modified chitosan (water soluble) as encapsulating agent. beta-galactosidase microparticles were prepared by a spray-drying method and were characterized in terms of particle size, surface morphology, zeta potential, and stability over a storage period of six months. Microparticles were also analyzed by FTIR spectroscopy and thermogravimetry techniques. Structural analysis of the surface of the particles was performed by scanning electron microscopy (SEM). SEM results show that the obtained microparticles have an average diameter smaller than 3.5 mu m and a regular shape. The beta-galactosidase activity decreases when microencapsulated. The parameters Km and Vmax of the Michaelis-Menten equation were calculated for the different experimental conditions. The optimal pH ranges from 6.4 to 7.2, approximately, depending on the enzyme concentration in the microcapsule. After six months of storage, the enzyme activity presents a small decrease, although no significant differences in the appearance, color, and particle size distribution were identified.