Surface properties of ion-inducted whey protein gels deposited on cold plasma treated support

Abstract

So far no studies have been undertaken on the influence of plasma processing of different solid surfaces on the properties of subsequently formed protein coat. Calcium chloride, magnesium chloride or iron (II) chloride inducing whey protein isolate gels were obtained on glass support previously treated with the plasma at the electric voltage 160 V per 1 min. Dynamic oscillatory and ultrasound viscosity measurements, scanning electron microscopy imaging, surface roughness and contact angles measurements have been performed. Apparent surface free energy was determined using the two approaches: van Oss, Good and Chaudchury (LWAB) and contact angle hysteresis (CAH). Gels surface roughness increased with the increasing of ions concentration. Both approaches used for determination of apparent surface free energy give comparable results. When the air plasma was applied for the support activation, polar groups deposited on the surface had a greater effect on the surface wettability than roughness. Plasma treatment of glass support caused the increase of hydrophobic properties of deposited layers. Wettability properties were affected by the electron donor parameter of energy whose value increased for the samples obtained on the plasma activated supports especially the air treated ones. Plasma treatment of glass plates might have an effect on food processing, production efficiency, microbiological aspects and cleaning process of the gels deposited on their surfaces.