Exploring starches from varied sorghum genotypes compared to commercial maize starch

Abstract

AbstractSorghum has been lately attracted the attention for human consumption as a gluten‐free cereal rich in bioactive compounds. Sorghum starches isolated from brown (BRS305), red (BRS308), and white (CMSXS180) genotypes were compared to commercial maize starch, based on proximate composition, particle size distribution, microstructure, X‐ray diffraction, amylose and total starch content, solubility index, swelling power, pasting, and thermal properties. The carbohydrate content of sorghum starch samples ranged from 98.24 to 99.23 g/100 g (dry basis). The particle size distribution of the CMSXS180 sorghum genotype was very similar to commercial maize starch. The relative crystallinity values varied from 29.83% to 30.39%. The water solubility index and swelling power of sorghum starches were lower than those of maize starch. Sorghum genotypes paste profiles were similar, but greatly differed from maize showing the highest final viscosity (4042.0–4444.5 cP) compared to maize starch (3767.5 cP) and lower gelatinization enthalpy (∆H = 9–10.5 J/g) than maize starch (11.8 J/g). The results showed some distinct properties of sorghum starches when compared to maize starch, which may contribute to provide alternative uses, particularly in food products requiring very high viscosity and retrogradation.Practical ApplicationsSorghum pericarp is rich in bioactive compounds, which can be used as a main source of ingredients, for example, to the nutraceutical industry. The sorghum grain without pericarp (decorticated), used to produce purified starch (without chemical treatment), may contribute to the total use of this cereal by limiting chemical residues. In addition, sorghum starch has shown particular technological properties different from commercial maize starch, providing alternative uses in the food industry, for example, in products that require high viscosity from hot to cold processes.