Genipin-functionalized magnetic materials: a sustainable and innovative method for immobilizing proteases to produce...

The use of enzymes in the food industry continues to expand, although challenges that still limit their large-scale applications like stability, reuse, and contamination. Enzyme immobilization on magnetic nanoparticles (MNPs) is an efficient strategy to overcome these limitations, enabling greater structural stability, enhanced catalytic activity, and easy magnetic recovery. In this study, magnetite nanoparticles were synthesized and functionalized with (3-aminopropyl)triethoxysilane (APTES) and genipin, a green alternative, resulting in a biocompatible and reactive support for the immobilization of trypsin and bromelain. Structural analyses (XRD, FTIR, zeta potential, SEM/EDS, and TGA) confirmed the magnetite crystalline phase and the successful surface modification, indicating linkage between the enzymes and the support. Immobilization efficiencies of 67.68% for bromelain and 65.19% for trypsin were achieved, maintaining high specific activities (8.14 and 60.85 U·g^-1, respectively). The immobilized enzymes presented operational stability and retained their activity after six reuse cycles. Casein hydrolysis with the immobilized enzymes yielded peptides with significant antioxidant potential (DPPH = 0.016 mg·mL^-1; ABTS = 55.60%; β-carotene/linoleic acid = 72.38%). Thus, the developed platform demonstrates high catalytic performance, combined with sustainability and reuse, and represents a promising alternative for biotechnological and industrial processes in the food sector.