Characteristics of sorghum flour modified with physical and enzymatic treatments

This study evaluated the physicochemical and thermal properties of modified sorghum flour. The modified sorghum flour was obtained through extrusion -enzymatic treatment using thermostable-α amylase at various feed moisture lev els. The results showed that unmodified sorghum flour had the average chemical composition of sample being 87.06% carbohydrate, 9.8% protein, 0.32% fat and 0.64% ash. The unmodified and modified sorghum flour differed in their properties. The swelling power and solubility changed from 16.21 (g/g) to 4.64(g/g) – 28.20 (g/g) and from 4.68% to 4.25%–83.81% respectively. A wide range of pasting properties were noticed, such as peak viscosity (54 cP-3028 cP), breakdown viscosity (59 cP-1029 cP), setback viscosity (-106.50–2351 cP). Peak viscosity was not detected when the modification was performed at high feed moisture (FM 35%) treatment combined with the addition of thermosta ble-αamylase. Additionally, the onset, peak, and conclusion temperatures of gelatinization, and the enthalpies of mod ified flours were lower than those of unmodified ones. Morphological changes in the surface of starch granules were noticed as shown by pore formation through SEM observation. This study provided insights into the future direction of extrusion combined with enzymatic treatment for the selective modification of sorghum flour functional properties