Physical and Chemical Modification of Sorghum Flour for the Potential Substitute of Wheat Flour

Abstract

The huge amount of wheat import causes efforts to find substitutes for wheat flour are very important in Indonesia. In this work, sorghum (Sorghum bicolor (L)) flour was physically and chemically modified. The physical modification was performed by heat treatment and/or addition of a foodstuff having high protein content (soybean or green beans flour). Heat treatment was conducted by heating in an oven at temperature of 100°C, 110°C and 120°C for various times (14, 15, and 16 hours). The chemical modification was carried out by addition of acetic acid (5%, 10%, 15%, 20%, 25% v/v) followed by heating at temperature of 60°C, 70°C, and 80°C. The unmodified and modified sorghum flour were then characterized in term of swelling power and solubility. Overall, sorghum modification by physical and chemical treatment increases both swelling power and solubility. The physical modification shows that modified sorghum flour by heating (only) at 100°C for 15 hours has swelling power was 12.39% and percent of solubility was 2.3%, which is closer to wheat flour than other physical modifications. The chemical modification by addition of acetic acid 15% v/v followed by heating at temperature of 70°C resulted in modified sorghum with the swelling power of 12.31, which approaches the swelling power of wheat flour (12.84).