Characterization of physicochemical and structural properties of atmospheric cold plasma (ACP) modified zein

- Atmospheric cold plasma (ACP) technology was used in powdery zein modification.
- Effects of plasma treatment on solubility of zein were investigated.
- The film forming properties of zein were studied.
- FTIR amide I deconvolution of treated zein was shown.

Atmospheric cold plasma (ACP) has been widely reported as an efficient approach in material surface modification. The effects of dielectric barrier discharge (DBD) ACP technology on the physicochemical and structural properties of powdered zein were investigated. The results indicated that the average diameter of zein particles decreased significantly indicating a depolymerization of aggregations after ACP treatment. There was an increase of free SH group concentration and decrease of pH in zein solutions. Significant improvement of zein solubility in both neutral and acidic solutions could be observed after treatment with max solubility at 75 V. Moreover, Differential Scanning Calorimetry (DSC) and X-ray diffraction (XRD) results indicated that ACP treatment rearranged the conformation. FTIR spectrum confirmed the change of secondary structure for amide I region (1600-1700 cm−1) after ACP treatment. Furthermore, the film forming properties of zein were also studied. It was found that the increase of ACP treatment voltage level could reinforce the tensile strength (TS) and surface hydrophilicity of zein films. It is suggested that the DBD ACP technology can effectively modify the physicochemical properties for protein powders.