Application of dielectric barrier discharge plasma to hydrophobically modification of gum arabic with enhanced surface properties

The aim of the present study was to evaluate the effect of cold atmospheric-pressure plasma (CAP) on the structural aspects and some physicochemical properties of gum arabic (GA), with emphasis on its surface properties. GA was treated at dielectric barrier discharge (DBD) plasma with ambient air for different times (20, 40, and 60 min). The optical emission spectroscopy (OES) was utilized to scope present active species in the plasma. Upon treatment, the structural, thermal and morphological variations, as well as changes in water contact angle, surface and interfacial tension, molecular weight, solubility, moisture content and color of the treated gums, were studied. Compared with GA, overall significant changes in the spectra of all treated gums were recognized, particularly in the range of 1200-1750 cm(-1). Elemental analysis of surface demonstrated that both oxygen and nitrogen content of treated gum increased time-dependently. Plasma had no pronounced effect on the amorphous nature of GA. Water contact angle data showed that plasma treatment was surprisingly capable of transforming GA hydrophilic nature into hydrophobic. The surface roughness of the treated gums powder time-dependently increased. The molecular weight, solubility, and moisture content of treated gum nonlinearly decreased with increasing treatment duration. The surface and interfacial tension significantly decreased after CAP treatment. The thermal properties and color of the treated gums changed after CAP treatment. In total, this study confirmed that the CAP treatment was an efficient approach to improve surface properties of gum arabic.