Techno-functional and gelling properties of acha (fonio) (Digitaria exilis Stapf) flour: a study of its potential as a new gluten-free starch source in industrial applications

Producción CientíficaFonio (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 (9.96ºC), 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.Ministerio de Economía y Competitividad - Fondo Europeo de Desarrollo Regional (project AGL2015-63849-C2-2-R)Ministerio de Ciencia, Innovación y Universidades (project PID2019-110809RB-I00)Junta de Castilla y León - Fondo Europeo de Desarrollo Regional (project VA195P20