Effect of traditional and radiofrequency assisted thermal processing on the gel firmness of egg white powder

Radiofrequency (RF) assisted thermal processing is a novel and energy-efficient method used for pasteurization, which heats the product volumetrically as opposed to traditional hot room (HR) pasteurization. RF-assisted thermal processing accelerates the heating rate of egg white powder (EWP), which has a very low thermal conductivity and further affect its gelling properties. In EWP, solubility plays a significant role in the water holding capacity of proteins, which affects the functional properties. The effect of processing methods (RF and HR) due to pH and treatment temperature combination is monitored by subjecting neutral EWP (6.4 pH) to 70 and 80 °C and alkaline EWP (pH 9.9) samples to 70 °C over 0, 5, 10, 15 and 20 d. RF processing substantially improved gelling properties. At 80 °C, the gel firmness was 48.6% higher than HR on the 0^th d, indicating RF could potentially improve the functionality as well as reduce the come-up time to less than a day as opposed to the traditional hot room processing used in the industry which takes 5–6 days. The treatment period also significantly affects the gel firmness and insoluble content. With increased treatment severity, the gel firmness substantially increased without changing the soluble protein contents, and insoluble contents.