Evaluation of sorghum inbred lines for milling quality

Abstract

Fourteen sorghum inbred lines and one sorghum variety were evaluated for qualitative parameters relating to milling quality. Grain hardness, flour yield, flour particle size and alkali water retention capacity criteria were measured. These quality criteria directly influence acceptability of newly established sorghum genotypes. Grain hardness was determined by measuring the time it takes to remove 30% of the kernel using a tangential abrasive dehulling device (TADD). Total flour extraction (flour yields) from decorticated pearled grains were ground into flour using a Brabender Quadrumat Jr. laboratory mill, and flour yields ranged from 96% to 100%. The flour was separated into three fractions by sieving samples through US #60 mesh (250 microns), and US #100 mesh (146 microns) mesh sieves for 160 s on a gyratory shaker to separate the flour into three different particle sizes: coarse (>US #60 mesh), medium coarse (< US #60 mesh >US #100 mesh) and fine (>US #100 mesh). Alkaline water retention capacity was determined by the amount of liquid that was retained in the flour paste after centrifuging and discarding excess supernatant. Significant differences were found for all criteria evaluated. The inbred line 293B had the softest endosperm and 256B, 257B, 266 B had the hardest endosperm. The inbred lines 256B and 257B were found to have the highest percentage of coarse flour. On the other hand 263B, 266B and 303B ranked the highest for medium coarse flour, and 266B yielded the highest percentage of fine flour. Inbred line 256B had the highest water retention for the coarse flour, 293B for medium flour and 296B for fine flour. The inbred line 266B was found to have the lowest water retention for the coarse flour.

Keywords:

• decortication
• milling quality
• particle size
• sorghum
• water retention