Assessing the Importance of Protein Interactions and Hydration Level on Protein-Enriched Gluten-Free Breads: a Novel Approach

The effect of starch substitution by 30% of different mixtures of egg white and pea proteins (100:0; 75:25; 50:50; 25:75; 0:100) was studied. The effect of hydration levels on specific volume was determined in order to later study the physical characteristics of different protein-enriched breads with an adjusted hydration level to achieve a specific volume similar to that of commercial wheat breads (5.5 ± 0.5 cm3/g). Hydration level needs to achieve this specific volume increase when increasing pea protein ratio. Control batter presented the highest elastic modulus, followed by the batter enriched with pea protein. Elastic modulus decreased progressively when increasing egg protein content. Same trend was observed for the viscous modulus. Differently, hardness was increased by the presence of egg protein, while decreased with the presence of pea protein. Breads with the same amount of both proteins showed no significant differences, compared to the control hardness. Regarding crumb structure, egg protein generated a uniform structure of small air bubbles that opened progressively when the proportion of pea protein was increased, until the same levels of both proteins were added, closing again with a higher pea protein content, but was not as close as when egg protein only was added.