Dielectric barrier discharge cold plasma-modified pea protein nanoparticles: enhancing functional and thermal properties for food and biopolymer applications

This study explored the use of dielectric barrier discharge cold plasma (DBD-CP) to produce Pea Protein Isolate Nanoparticles (PPI-NPs) at 30 kV for 2, 4, 6, and 8 min. Increasing the voltage and extending the treatment time led to larger nanoparticle sizes and more irregular morphology. Samples treated with CP showed higher absorbance in the 230–300 nm range, while fluorescence intensity decreased as the treatment time increased. CP exposure altered the FTIR spectra, particularly the amide I and II bands. The plasma-treated PPI-NPs exhibited increased surface hydrophobicity and carbonyl content and reduced free sulfhydryl (SH) groups compared to untreated samples. Additionally, the water and oil holding capacities and solubility of PPI-NPs improved with longer treatment durations. Thermal analysis revealed that CP exposure at 30 kV for 6 and 8 min increased the denaturation temperature (T_d) to 112 °C and 114 °C, respectively. At the same time, the untreated sample had a T_d of 110 °C, indicating enhanced cross-linking of polar functional groups. These results suggest that CP treatment effectively improves the functional properties of protein nanoparticles, making them suitable for applications in food packaging and pharmaceuticals.