Abstract: This study aimed to develop a core-shell carrier based on natural plant microcapsules for use as a delivery system for Lactobacillus plantarum and β-galactosidase (β-Gal). Sporopollenin exine capsules (SECs) were used as the core, and calcium-alginate (Ca-Alg)/carboxymethylpachymaran (CMP) as the shell. The probiotics loading capacity and the residual activity of β-Gal were 9.63 × 109 CFU/g and 80.72%, respectively. The introduction of CMP could affect the swelling behavior and microstructure of the shell and, consequently, the release behavior of probiotics and enzymes by changing its water-binding capacity. The introduction of CMP improved the gastrointestinal stability of Ca-Alg/CMP coated SECs loaded with L. plantarum and β-Gal. After 600 min of culture under simulated gastrointestinal conditions, the number of viable cells exceeded 107 CFU/mL, and the residual activity of β-Gal was around 62%. Compared with the control group (pure L. plantarum and β-Gal), the system could significantly reduce the loss rates of the probiotic cell count and β-Gal activity after lyophilization and during storage (P < 0.05). Finally, using methylcellulose (MC) to coat the core-shell structure could significantly improve the thermal stability of L. plantarum and β-Gal (P < 0.05).

Key words: sporopollenin exine capsules; core-shell structure; carboxymethylpachymaran; probiotic; enzyme; stability