Effectiveness of dry-fractionated pea protein concentrate to prepare gluten-free focaccia flatbread with optimal sensory, textural and nutritional profile

The aim of this work was to formulate a gluten-free focaccia flatbread fortified with pea protein concentrate (55 g/100 g protein content), and optimize its sensory and nutritional profile. Focaccia is a traditional Italian garnished flatbread, widely appreciated throughout the entire country, prepared with wheat flour, vegetable oil, yeast and salt (Pasqualone et al., 2022). This bakery product has not been formulated in a gluten-free version yet, despite the increased request of gluten-free foods. Gluten-free bakery products are often characterized by a poorer nutritional composition compared to the conventional counterpart, being rich in lipids and poor in proteins. Pulses are characterized by high content of proteins, fibers, micronutrients and phytochemicals. The pea protein concentrate was obtained by dry fractionation, a more sustainable technology of protein enrichment compared to wet fractionation. A simplex-centroid mixture design with seven formulations and three replicates helped to study how the flour ratios influenced the physical and sensory properties of dough and breads. The special cubic model significantly described all the responses determined in the dough and flour mixes, and most of those determined in the focaccia. The addition of pea protein concentrate led to an increase of water absorption index (WAI) and a decrease of water solubility index (WSI), thus influencing the pasting properties of the flour mixes with a decrease of apparent viscosity, probably due to the starch dilution as the protein content increased. The midpoint of the experimental domain (focaccia containing 5 g/100 g of pea protein concentrate and 40 g/100 g of a 50:50 blend of rice and corn flours) appeared to be the optimal focaccia formulation (De Angelis et al., 2023) (Figure 1). This level of pea protein concentrate, indeed, allowed to avoid the typical discolorations of pea. The color coordinates a* and b* accounted for 11.97 and 31.86, respectively, corresponding to a pale orange. Moreover, crumb hardness and chewiness accounted for 9.11 N and 4.83 N, respectively, and legume odor and flavor were moderate (5.6 and 5.3 c.u. in a 0-9 scale, respectively). The optimized focaccia could be labelled as “source of protein” (energy value provided by proteins >12%), “source of fiber” (fiber >3 g/100g), and “low-fat” (fat <3 g/ 100 g).