Influence of milling methods and particle size on hydration properties of sorghum flour and quality of sorghum biscuits

The sorghum flour of different particle sizes (251, 178, 152, 104 and 75 mu m) made from traditional milling process and hammer mill were obtained using different sieves and evaluated for hydration properties. Biscuits were prepared using the respective flours of various particle sizes and the physical, textural and organoleptic properties were evaluated. With the decrease in particle size of flour, the water absorption capacity (P < 0.05) and swelling power (P < 0.01) increased, Water binding capacity and oil binding capacity decreased (P < 0.05) in hammer milled flour than traditionally milled flour. The hardness (texture) was higher in biscuits prepared from flour of particle size 152, 104 and 75 mu m compared to 251 mu m and 180 mu m. The color of biscuits was affected by the milling process, L* and b* were higher (P < 0.01) in hammer milled flour and a* and whiteness index were higher in traditionally milled flour. Acceptability was higher in biscuits prepared from the traditionally milled flour of particle sizes 251 mu m and 180 mu m. (C) 2015 Elsevier Ltd. All rights reserved.