Exploiting pitaya cladodes for protease Extraction: Immobilization on nanomaterials and its role in antioxidant production

Abstract

This study aimed to explore pitaya (dragon fruit) cladodes as a novel source for extracting proteases. Various extraction methods were tested, focusing on evaluating the protein recovery and the proteolytic activity of the crude extracts. The best condition was obtained using 1 M NaOH and sodium acetate (0.1 M, pH 5.0) combined with 2 % Viscozyme L yielded the highest protein recovery and enzymatic activity. The extracted proteases exhibited optimal activity at acidic pH levels and temperatures between 30 °C and 40 °C, and they were stable in the presence of metal ions. Kinetic parameters for the proteases were determined, with Km values ranging from 0.023 to 0.377 mg/mL and Vmax values from 2.893 to 4.328 μmol/(Tyr.min). The difference in the profile of proteins can be visualized by electrophoresis and exclusion chromatography. When immobilized on graphene oxide, the proteases from the crude extract retained up to 70 % of their activity with an immobilization efficiency of 60.75 %. However, changes in the structure of the proteases did not impact antioxidant properties (DPPH, FRAP, and β-carotene assays). Overall, proteases extracted from pitaya cladodes and immobilized on graphene oxide present a promising approach for producing bioactive compounds with significant commercial potential in the food and pharmaceutical industries.