The quality of quinoa flour is greatly determined by its non-starch components, mainly protein and lipids. Dry fractionation has an important impact on the composition and physicochemical properties of quinoa flour and grits. Quinoa cv. Titicaca, the most extensively grown in Europe and little studied so far, was used in this work. Hydration, techno-functional, rheological and thermal properties of three quinoa fractions obtained by dry fractionation (fine, medium and coarse) were evaluated and related to their particle size and composition. The medium fraction (~500 μm) was enriched in protein (50%) and lipids (80%) and depleted in starch (30%) with respect to the original grain; while the coarse fraction (~1000 μm) was enriched in starch (7%) and reduced in protein (15%). The fine fraction showed the most similar functional, pasting and rheological properties to the whole grain quinoa flour. The coarse fraction led to the most consistent gels, with the elastic (G') and viscous (G'') moduli being ten and twenty times higher than those found in the other quinoa fractions and the whole grain flour. The degree of retrogradation as well as the formation of the amylose-lipid complex were markedly affected by the particle size and not so by the composition of each fraction. This work allows to conclude that dry fractionation of quinoa grains is a feasible procedure to tailoring the nutritional profile of the flour and its techno-functional and rheological properties.

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The addition of bioactive β-glucan to gluten-free breads is of special interest to people suffering from celiac disease. Most of the studies found in literature involve cereal (1 → 3)(1 → 4)-βglucan, while those from yeast and fungi are still nearly unexplored. This study focuses on the effect of fortifying gluten-free rice-based doughs and breads with (1 → 3)(1 → 6)-β-glucan concentrates derived from yeasts -soluble (SBG) and insoluble (IBG)-and fungi (Pleurotus Ostreatus) (FBG). SBG-enriched doughs were less firm and exhibited lower resistance to deformation than doughs with FBG or IBG. In contrast, FBG-and IBG-enriched doughs increased their resistance to deformation as the concentration increased. Doughs with a firmer consistency as determined by a forward extrusion test (FBG-and IBG-enriched doughs) corresponded to those with larger dynamic moduli and lower frequency dependence, lower elastic deformation and higher viscosity at steady state. The physical quality of breads was significantly improved by addition of all types of (1→3)(1→6)-β-glucan at optimized dough hydration. They caused an increase in the specific volume of the breads, a reduction in their hardness and longer shelf-life. Sensory evaluation also demonstrated an improvement in bread organoleptic attributes when SBG was added.

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Fonio (Digitaria exilis Stapf) is an ancient African cereal that represents a rich source of carbohydrate, fat, fiber, vitamins, minerals, and sulfur-containing amino acids. Processing and utilization of fonio require adequate knowledge of its structural, chemical, and nutritional characteristics. The present work evaluates the structural, techno-functional, and gelling properties of fonio and compares them to other major gluten-free cereals (rice, maize, sorghum, and millet). Fonio flour presented significantly higher water absorption index and swelling power, while it scored a lower water solubility index than the reference flours. The pasting viscosity profile of fonio was similar to that of rice, with equivalent peak viscosity but a breakdown viscosity 24% lower than rice, indicative of higher stability and resistance to shearing and heating. Rheological properties demonstrated that fonio generates gels with remarkably strong structures. At 15% concentration, fonio gel withstood stress 579% higher than those observed in the reference flours without breaking its structure. Fonio flour presented the highest gelatinization enthalpy (11.45 J/g) and a narrow gelatinization temperature range (9.96 °C), indicative of a better-packed starch structure than the other analyzed flours. The texture of the gels made with fonio showed higher firmness over the evaluated period. These combined results suggest that fonio is a suitable ingredient for gel-like food formulations.

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