Enhancement of biological properties in casein protein through functionalization with cinnamaldehyde via Schiff base bonding: antibacterial and antioxidant effects

This study investigates the modification of casein protein with cinnamaldehyde via Schiff base bonding, aiming to enhance its biological properties. The functionalization process was validated through different analytical techniques, including Fourier Transform Infrared Spectroscopy (FTIR), which confirmed the formation of Schiff base linkages. Thermal Gravimetric Analysis (TGA) and Scanning Electron Microscopy (SEM) were employed to assess the thermal stability and morphological changes of modified protein, respectively. Biological evaluations revealed that the cinnamaldehyde-functionalized casein exhibited significant antibacterial activity against four different bacteria strains [two Gram-positive (Staphylococcus aureus and Bacillus cereus) and two Gram-negative (Escherichia coli and Pseudomonas aeruginosa)], showcasing its potential as an antimicrobial agent. Antioxidant tests demonstrated enhanced scavenging abilities, suggesting protective effects against oxidative stress. Furthermore, preliminary hemocompatibility assessments indicated that the modified protein is non-toxic to human blood cells, underscoring its suitability for biomedical applications. Collectively, these findings suggest that cinnamaldehyde-functionalized casein holds promise for advancing healthcare materials.