Improving the thermal stability of phytase using core-shell hydrogel beads

Abstract

A core–shell hydrogel bead system was designed to maintain the catalytic activity of phytase and protect its enzymatic functionality from heat treatment. The designed structure consists of a chitosan-phytase complex core and an alginate-carrageenan hydrogel shell. The core–shell hydrogel was optimized to improve phytase encapsulation efficiency and increase the thermal stability of the encapsulated phytase. After heat treatment, encapsulated phytase retained ∼ 70 % of its catalytic activity and the same secondary structure of free phytase. Fourier transform infrared spectroscopy indicated strong intermolecular interactions between chitosan and phytase in the core, but little interaction between the core and the alginate and κ-carrageenan shell, this supports the structural and functional stability of the phytase. Differential scanning calorimetry confirmed that the designed core–shell structure had a higher melting point. Encapsulating phytase in a core–shell hydrogel bead can enhance the thermal stability of phytase, which broadens the potential applications for phytase delivery.

Keywords

• Core-shell hydrogel
• Chitosan
• Alginate
• κ-Carrageenan
• Phytase
• Thermal Stability