Experimental investigation of egg ovalbumin scaling on heated stainless steel surface and scale-removal compared with that of whey protein

Fouling and cleaning on a heat exchanger surface during milk processing have been studied extensively in the past due to their great importance in energy, product quality, and safety. However, little information is available for egg ovalbumin (OVA) fouling and cleaning behavior. In the present work, fouling and cleaning behaviors of OVA were investigated using a real-time monitoring system for heat transfer coefficient. A comparison was made between the behavior of whey protein concentrate (WPC) and that of OVA. WPC has been well studied which can be used as a benchmark. Ultrasonic cleaning was also applied to investigate the cleaning behavior of OVA fouling. Results have shown that OVA created more thermal resistance than WPC in the 2 h fouling process. It was also much more difficult to remove the OVA deposit than the WPC fouling. Different from what were observed from WPC deposit, there was no optimal cleaning rate for OVA deposit in the NaOH concentration range tested (0–2.0 wt%), while WPC fouling is known to have the highest cleaning rate around 0.5 wt% NaOH concentration at moderate temperatures.

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► OVA fouled more intensively than WPC on the heat transfer surface.
► OVA fouling was much more difficult to be removed than WPC.
► The theories for WPC may not be suitable to explain OVA fouling and its cleaning.
► There was no optimal cleaning rate for OVA fouling with NaOH from 0 to 2.0 wt%.