Influence of grain germination on functional properties of sorghum flour

Abstract

A Sudanese sorghum cultivar (Fetarita) was germinated for five days and protease and amylase activities were measured every 24 h. Results showed that flour obtained from the 3rd germinated sorghum grain had high protease and amylase activities. The functional properties of flours derived from the germinated sorghum seeds were studied and ungerminated seeds were used as a control. Germinated samples had a higher protein solubility compared with the control, and the highest solubility occurred at pH 6. Germination also increased the protein solubility index of sorghum flour. Germinated sorghum flour had a least gelation concentration of 8% compared with 18% for the control. The bulk densities of germinated flours were lower compared to the ungerminated one. Water and oil capacities were increased by germination from 131.34% and 90.56% to 141.64% and 108%, respectively after three days of germination. The emulsifying activities and stabilities of the germinated samples increased significantly. In addition, germination improved the foamability of sorghum flour from unfoam flour to a flour with foam after three days of germination; and the foaming capacity and stability increased significantly with increasing germination time. Thus, the study indicated that germination improved the functional properties of sorghum and it would be possible to design new foods using germinated sorghum.