Effect of initial product temperature and initial pH on foaming time during vacuum evaporation of liquid whole eggs

During earlier studies on vacuum concentration of liquid egg white, the phe nomena of foaming during the initial stages of the process were reported. I n these studies, it was also shown that no concentration took place during the foaming period that varied from test to test. To minimize the total pro cess time, this present study was undertaken to investigate what variables contributed to foaming, how they could be controlled, and what effect they had on product quality and functional properties. This study investigated the relationships among initial product temperature , initial pH, and foaming of Liquid whole eggs. Two temperatures (9 and 20 C) and three pH levels (6.5, 7.3, and 8.5) were studied using a vacuum evap oration system with a maximum vacuum of 5 kPa. Tests showed that higher ini tial pH levels had decreased foaming times. At the end of foaming experiments, the liquid whole egg was evaluated to de termine the extent of functional property change during foaming. A decrease in foaming time resulted in a decrease in whip time. The cakes made from t he processed liquid whole egg had larger volumes than those from the unproc essed control. Furthermore, the liquid whole egg, which foamed the longest, had higher (P < 0.05) cake volumes. Our current experiments also verified our earlier findings that no product concentration takes place during the f oaming process.