Optimization of Penicillium aurantiogriseum protease immobilization on magnetic nanoparticles for antioxidant peptides' obtainment

摘要

This work reports an optimization of protease from Penicillium aurantiogriseum immobilization on polyaniline-coated magnetic nanoparticles for antioxidant peptides' obtainment derived from bovine casein. Immobilization process was optimized using a full two-level factorial design (2(4)) followed by a response surface methodology. Using the derivative, casein was hydrolyzed uncovering its peptides that were sequenced and had antioxidant properties tested through (2,2-Azino-bis(3-ethylbenzothiazoline-6-sulfonic acid) diammonium salt) (ABTS) radical scavenging and hydrogen peroxide scavenging assays. Optimal conditions for immobilization were 2hr of immobilization, offered protein amount of 200 mu g/mL, immobilization pH of 6.3 and 7.3hr of activation. Derivative keeps over 74% of its original activity after reused five times. Free and immobilized enzyme casein hydrolysates presented similar peptide mass fingerprints, and prevalent peptides could be sequenced. Hydrolysates presented more than 2.5x higher ROS scavenging activity than nonhydrolyzed casein, which validates the immobilized protease capacity to develop casein-derived natural ingredients with potential for functional foods.