Different reaction times for phosphorylation of sorghum flour (Sorghum bicolor): Physicochemical evaluation and application in the formulation of gluten-free cakes

Abstract

The aims of this study were to examine the phosphorylation of sorghum flour at different reaction times, evaluate the properties of modified flour, and apply the phosphorylated sorghum flour at different concentrations in the production of gluten-free cakes. The phosphorylated sorghum flour showed reduction in the following parameters: amylose content (about 13% reduction), syneresis (39%), and retrogradation (about 68%), when compared to native flour. Additionally, the phosphorylated flour showed greater swelling power and water solubility depending on the temperature of the water used. Gluten-free cakes were prepared with 10, 20, 30, 40, and 50% substitution of the premade mix using native or phosphorylated sorghum flours. Cakes were evaluated for baking loss, specific volume, and texture characteristics. When comparing cakes produced with phosphorylated sorghum flours to the control, the baking loss did not show significant difference, considering flour concentrations up to 50% substitution. In this percentage (50%), the baking loss was 14% for phosphorylated flour. The incorporation of 20 and 40% phosphorylated sorghum flour increased the specific volume in 5 and 10%, respectively. Substitution of a ‘control gluten free premade mix’ with up to 20% phosphorylated sorghum flour decreased the hardness of cakes while substitution with 40% and 50% phosphorylated sorghum flour decreased chewiness of cakes. The substitution of native flour by up to 50% phosphorylated sorghum flour is feasible and promisor to produce gluten-free products with improved properties. The cakes produced in this study can be inserted in the new food sector of gluten-free and healthy products.