Optimized immobilization of Chenopodium murale phytase for functional food

In this study, three phytase solid carriers AlgNa/PVA beads, glass microspheres, and cellulose beads were evaluated for their ability to reduce phytic acid in various foods. Phytase was either entrapped in the carriers or covalently immobilized onto the substrates for application. Among these, glass microspheres were selected due to their remarkable catalytic efficiency. The chromogenic indicator p-nitrophenyl phosphate disodium salt hexahydrate was used to assess enzyme activity under selected conditions (pH 5.5, 50 °C). The reaction rate constant (K) was calculated as 0.024 min⁻¹, while the time to hydrolyze 50 % of phytic acid (τ₅₀) and the time for complete hydrolysis (τ_complete) were determined as 36.1 min and 110 min, respectively. The activity of the free phytase enzyme was significantly reduced by all tested metal ions (Cu²⁺, Hg²⁺, Fe²⁺, Mg²⁺, Zn²⁺, and Ca²⁺), whereas only Mg²⁺ showed an inhibitory effect on the immobilized enzyme, highlighting the protective role of immobilization. The ability of both free and immobilized phytase to hydrolyze phytic acid in various food matrices broad beans, chickpeas, peanuts, peas, pinto beans, brass, maize, dry corn, oats, rye, wheat, green lentils, and red lentils was examined. Although pH 5.5 and 50 °C promoted enzymatic activity, it is important to emphasize that a comprehensive optimization involving multi-variable experimental design was not conducted. Therefore, these conditions should not be interpreted as true optimal conditions, and further optimization studies are recommended.