Three small-scale laboratory steeping and wet-milling procedures for isolation of starch from sorghum grains cultivated in Sahara of Algeria

Abstract

Starch was isolated from white and red sorghum. The values of thousand kernel weight, test weight, starch and protein contents were respectively 33.05±0.5 (g), 692.85±0.65 (g/l), 65.05±0.19% and 12.27±0.18% for the white sorghum grains and 27.70±0.13 (g), 736.55±0.25 (g/l), 66.37±0.31% and 12.59±0.03% for the red sorghum grains.Three small-scale laboratory steeping procedures were used: steeping in NaOH solution, in SO2 solution and in SO2 solution containing lactic acid. The effect of the concentration of steeping solutions and time of steeping on starch isolate and yield were studied. The starch recovery, starch purity, moisture, amylose, protein content and particle size distribution ranged from 64.8% to 80.4%, 92.61±0.54% to 99.29±0.55%, 11.84% to 14.43%, 27.71±0.41% to 29.88±0.56%, 0.31±0.01% to 0.78±0.01% and 4.0μm to 36μm, respectively.The high grain quality traits and isolated starch properties indicated that Algerian sorghum cultivars can have many applications in nutrition and food technology.