Design of a "Clean-Label" Gluten-Free Bread to Meet Consumers Demand

Abstract

The market of gluten-free (GF) products has been steadily increasing in last few years. Due to the technological importance of gluten, the GF food production is still a challenge for the industry. Indeed, large quantities of fat, sugars, structuring agents, and flavor enhancers are added to GF formulations to make textural and sensorial characteristics comparable to conventional products, leading to nutritional and caloric intake imbalances. The formulation of the novel "clean-label" GF bread included a commonly used mixture of maize and rice flour (ratio 1:1) fortified with selected protein-rich flours. Naturally hydrocolloids-containing flours (psyllium, flaxseed, chia) were included in the bread formulation as structuring agents. A type-II sourdough was obtained by using a selected Weissella cibaria P9 and a GF sucrose-containing flour as substrate for fermentation to promote the exo-polysaccharides synthesis by the starter lactic acid bacterium. A two-step protocol for bread-making was set-up: first, the GF sourdough was fermented (24 h at 30 °C); then, it was mixed with the other ingredients (30% of the final dough) and leavened with baker's yeast before baking. Overall, the novel GF bread was characterized by good textural properties, high protein content (8.9% of dry matter) and in vitro protein digestibility (76.9%), low sugar (1.0% of dry matter) and fat (3.1% of dry matter) content, and an in vitro predicted glycemic index of 85.

Keywords: clean-label; gluten-free bread; sourdough.

Figure 1

Evaluation of leavening performances on dough and bread made with rice and corn flours and supplemented with 10% of protein-rich () and structuring () flours (QUI, quinoa; TEF, teff; CHP, chickpea; FAB faba bean; LUP, lupin; LEN, lentil; PEA, pea; FLA, flaxseed; CHI, chia; HCHI, hydrated chia; PSY, psyllium). (A): Volume increment of dough after leavening (2 h at 30 °C); (B): Alveolus percentage of bread slice; (C): Specific volume of bread. ^a–e Bars with different letters differ significantly (p < 0.05)

Figure 2

Representative images including digital images of bread showing the original gray-level images and computed binary results from gray-level thresholding at the two-cluster of bread crumb. b-CT (A), bread made with rice and corn flours (ratio 1:1) and 6% (wt/wt) of structuring flours (psyllium, hydrated chia, and flaxseed, ratio 4:1:1); b-S (B), bread made with rice and corn flours (ratio 1:1), 30% (wt/wt) of s-C20, and 6% of structuring flours (psyllium, hydrated chia, and flaxseed, ratio 4:1:1); b-ST (C), bread made with rice and corn flours (ratio 1:1), 30% (wt/wt) of s-C20, 10% (wt/wt) of teff flour, and 6% of structuring flours (psyllium, hydrated chia, and flaxseed, ratio 4:1:1); b-SL (D), bread made with rice and corn flours (ratio 1:1), 30% (wt/wt) of s-C20, 10% (wt/wt) of red lentil flour, and 6% of structuring flours (psyllium, hydrated chia, and flaxseed, ratio 4:1:1); b-SQ (E), bread made with rice and corn flours (ratio 1:1), 30% (wt/wt) of s-C20, 10% (wt/wt) of quinoa flour, and 6% of structuring flours (psyllium, hydrated chia, and flaxseed, ratio 4:1:1). All doughs had DY of 200. Baker’s yeast was used at 1.25% (wt/wt). Proofing was at 30 °C for 2 h and baking at 200 °C for 45 min.