Investigation into the impact of egg white addition on the structural properties and flavour profile of gluten-free sourdough bread

Abstract

The impact of egg white addition on structural and sensory qualities of gluten-free sourdough bread was investigated at three egg white-to-sourdough ratios: 25:75, 45:55, and 85:15, versus a sourdough-only control (0:100) Previously, egg white has replicated gluten-like networks, and sourdough addition improved structural and storage qualities in gluten-free breads. In this study, mild acidity from sourdough promoted gluten-like network formation in egg white-added breads, evidenced by significantly thicker cell walls versus control (p < 0.05), with the greatest improvement in samples with 45 % egg white and 55 % sourdough. Specific volume and textural parameters of breads with 45–85 % egg white were significantly improved versus control (p < 0.05). Principal Component Analysis showed positive multivariate correlations between egg white content and improved chewiness, area of cells and density. Positive correlations were identified between sourdough content and favourable acetic acid, phenylethyl alcohol and 6-methyl-5-heptan-2-one, and samples with egg white-to-sourdough ratios 45:55 contained positive flavour attributes throughout storage, with the greatest concentrations of acetic acid and phenylethyl alcohol by day six. This research demonstrated that the combination of egg white and sourdough in similar proportions promotes the formation of gluten-like networks, producing gluten-free breads with similar structural and sensory attributes to conventional breads, which are retained over storage.