Foams from egg white showed potential as structure builders by retaining gas and forming continuous networks in sourdoughs, according to findings published in the Journal of Agricultural and Food Chemistry.
“This study showed that the use of egg white foam substantially improved the structural quality of model baked goods which were prepared from sourdough and potato starch,” wrote the researchers, led by Jussi Loponen from the University of Helsinki.
“The use of egg white foam in the starch based sourdough baking recipes could serve as an alternative way to build up structure in low-gluten bread making applications,” they added.
Great hopes for sourdough
Sourdough has already been identified as an ideal gluten-free food. Only recently, Professor Elke Arendt from the Department of Food and Nutritional Science at University College Cork co-authored a review in the journal Food Microbiology on the how sourdough could help solve the gluten-free issue.
Prof Arendt told FoodNavigator recently: “Sourdough has a lot of potential, particularly from a flavour and structure perspective. The strains used are also anti-fungal and that can extend the shelf-life of bread without the need of chemical preservatives.”
But employing sourdoughs requires a detailed knowledge of the strains and starter cultures for each grain. Sorghum sourdough would need a specific strain, like Lactobacillus reuteri or Lactobacillus fermentum, while buckwheat flour would require other starter cultures.
“I have great hopes for sourdough in gluten-free bread,” said Prof Arendt.
And with global market reported to be worth $2.6bn by 2012, up from $1.56bn last year, according to Packaged Facts, there is clearly the financial incentive to produce new foods for this category.
The new joint Turkish-Finnish study investigated the how egg white could build foam structures with sourdoughs, as well as looking at how the egg proteins may affect fermentation parameters. The latter point is important as egg white proteins are known to exhibit antimicrobial activity, which is undesirable in sourdough formulations.
No effect on the fermentation parameters was observed, said the researchers. “The presence of egg white in sourdough fermentations had no influence on the prolamin hydrolysis or the growth of starter culture, indicating that the peptidase-inhibitory and antimicrobial properties of egg white play no important role in sourdoughs,” they wrote.
In terms of foam formation, the egg white was found to be structure builders in sourdough applications.
“The present study showed that a convenient way to form foams containing both egg white and sourdough was to first whip egg whites into foam and then mix in the fermented sourdough,” wrote the researchers.
Source: Journal of Agricultural and Food Chemistry
Published online ahead of print, doi: 10.1021/jf903228x
“Functional Characteristics of Egg White Proteins within Wheat, Rye, and Germinated-Rye Sourdoughs”
Authors: F. Erem, T. Sontag-Strohm, M. Certel, H. Salovaara, J. Loponen