A Study of the Effects of Surface Chemistry on the Initial Deposition Mechanisms of Dairy Fouling

Abstract

The initial interactions between milk protein components and surfaces with varying surface chemistry are the main focus of this study. The research draws from the expectation that suitable modification of heating surfaces may minimise the effects of protein fouling and/or decrease the deposit adhesion strength to facilitate simpler cleaning procedures. Samples to be fouled were placed in a flow-through rig, and whey protein fouling solutions were pumped through the rig to flow past the samples. Fouling times were kept under 3 min in order to study the deposit forming during the initial stages at elevated temperatures. Whey protein deposits were formed on stainless steel and diamond-like carbon (DLC) coated stainless steel surfaces. Compositional analysis of the deposit formed on the surfaces was performed using X-ray photoelectron spectroscopy (XPS). Possible protein functional groups were identified by analysing the C, O and N components on the surface. Angle resolved XPS allowed determination of groups which may be involved in bonding. Preliminary results suggest bonding on Si-doped DLC involves N containing groups and C—OH groups. Similar analyses are being performed for stainless steel and standard DLC surfaces. These initial results will be further verified and accompanied by measurement of deposit weight and removal characteristics to better determine the effect of modification.