Effect of acetylation and varietal differences on the pasting properties of some corn starches
AbstractThe pasting properties of starch from eight varieties of corn; Okomasa, Obatanpa, Dodzi, Mamaba, Dadaba, Dorke, Golden crystal, and CIDA-ba were studied to establish the effects of acetylation and varietal differences on the pasting properties. Native starches extracted from the
corn varieties were modified with 10% v/v acetic anhydride solution. The pasting properties studied included pasting temperature, peak viscosity, breakdown, and retrogradation. The pasting temperature, peak viscosity, viscosity at 95°C and 50°C, breakdown and retrogradation of the
native starches were generally higher than those of the acetylated starches. The pasting temperature of the native starches was between 67.6-78.2°C and acetylated starches between 65.5-77.2° C. The Native Okomasa and acetylated Golden crystal had the highest pasting temperature of 78.2°C and peak temperature of 94.6°C respectively. The acetylation had significant effects (p<0.05) on the pasting properties except pasting temperature. With the exception of pasting temperature, varietal differences significantly affected (P<0.05) the pasting properties of the starches. The acetylation improved the pasting properties of the native starches, thus enchancing their application in food products. All the varieties of corn had good pasting properties; however, in terms of breakdown and retrogradation, Golden crystal is the most preferred variety.