Effect of dry heat and guar gum on foaming properties of egg white powder and cake quality
School of Food Science and Technology, Jiangnan University, Jiangsu WuXi 214122
Abstract： In this paper, the dry heat treatment, guar gum addition, whipping process and structure properties of egg white powder (EWP) were discussed. The application of modified EWP in angel cake was also discussed. Using foaming capacity as the index, dry heat time, amount of guar gum (GG), whipping time and protein concentration as variables, which can determine the best modified and whipping conditions. The functional properties of EWP with different modified degree were analyzed. DSC and FTIR were also used to characterize the structure of those EWP. The improved degree of angel cake by modified EWP was measured with cake specific capacity and texture. The result showed that the optimum process were dry heat time 10d, GG addition 0.4%, whipping time 21min and concentration 14%. Under these conditions, foaming capacity and foam stability were best. Two modified methods could increase the viscosity and surface hydrophobicity and decrease the surface tension of solution synergistically, thus improving foam stability and foaming capacity. Meanwhile, protein space structure was significantly changed by dry heat, which caused more amino acid residues exposed. Those two modified methods could change the proportion of secondary structure prediction, which promoted the increase of hydrophobicity and foaming properties. In addition, modified EWP (EWP10+GG) could significantly enhance cake specific volume, and its angel cake was soft and elastic.