Grain characteristics and composition of selected new Sorghum lines

Abstract

The aim of the present study was to investigate the nutritional and technological properties of new sorghum lines. Grain characteristics (pericarp thickness, hardness, bulk density, kernel size, thousand kernel weight, endosperm structure); proximate composition; amylose/amylopectin; functional properties (Water solubility index, swelling power); and pasting properties of 28 new sorghum lines were determined. The results showed varietal differences (p<0.05) with respect to grain characteristics, grain composition and grain functional properties. Grain characteristics results for the different sorghum lines ranges were 20.9 to 36.2 g for thousand kernel weight; 67.2 to 182.5 N for kernel hardness; 0.05 to 0.14 μm2 for corneous endosperm surface area; 0.07 to 0.20 μm2 for floury endosperm surface area; 7.7 to 13.5 μm for pericarp thickness; and 0.74 to 0.82g/cm3 for bulk density. The composition of the different sorghum lines ranges were 89.4 to 92.2% for dry matter; 61.1 to 79.1 % for Starch; 8.3 to 11.4% for protein; 1.6 to 3.5% for fat; 3.2 to 7.0 % for dietary fibre; and 1.2 to 1.9 % for ash. The amylose/amylopectin ratio ranged from 0.30 to 0.66. Sorghum lines namely MAGIC26, MAGIC05, MAGIC14, MAGIG02, MAGIC10, MAGIC12, MAGIC13, MAGIC14, MAGIC20, and MAGIC18 contained condensed tannins ranging from 70.2 to 189.4mg/100g. Functional properties namely swelling power and water solubility index varied from 0.01 to 0.04 and 4.5 to 5.5, respectively. The pasting properties were 782.00 to 2512.0RVU peak viscosity; 190 to 1030RVU breakdown; 671.00 to 5842.5RVU final viscosity; 471.00 to 4033.50RVU setback viscosity; and 78.33 to 92.28oC pasting temperature for the different sorghum lines. Seasons did not appreciably affect most of the measured parameters (< 0.05). The results suggest that the different sorghum lines can be selected to suit specific food and non-food applications.