Physico-Chemical, Pasting and Sensory Properties of Food Blends of Maize, Yellow Cassava or Sweet Potato Starch, Defatted Soybean and Groundnut Flour

Abstract

Gruel was produced from different formulations of maize, yellow cassava or sweet potato starches; defatted soybean and groundnut flours. Eighteen blends were produced with 100% maize as the control. The recipe formulations for the products were 100:0:0, 90:5:5, 85:10:5, 75:20:5, and 70:25:5 of the various starches, soybean and groundnut flours respectively. The eighteen formulated products were subjected to chemical, functional, pasting and sensory analysis. There were significant differences (p≤0.05) in all the parameters investigated. The protein content ranged from 0.50 to 20.45%, fat content from 0.29 to 8.93% while the ash content ranged from 0.09 to 1.24%. The moisture values ranged from 9.5 to 14.15%, while carbohydrate content ranged from 60.14 to 84.22%. Amylose and amylopectin ranged from 21.06 to 29.25% and from 70.75 to 78.94% respectively. Starch and sugar contents ranged from 2.48 to 4.95% and from 56.57 to 70.15% respectively. The functional properties also varied due to differences in starch sources. Dispersibility ranged from 69.00 to 81.25% while bulk density ranged from 0.31 to 0.53g/ml. Swelling power and solubility ranged from 6.02 to 8.30% and from 1.30 to 14.39% respectively. Water absorption capacity ranged from 0.77 to 2.16% and least gelation concentration from 4 to 8%. Pasting properties of the starches showed that peak and break down viscosities ranged from 158.18 to 620.54RVU and 63.43 to 419.38RVU. Trough and final viscosities ranged from 92.90 to 241.48RVU and 157.00 to 310.72RVU, while setback viscosity value ranged from 50.12 to 113.25RVU. Pasting time ranged from 3.55 to 4.61min, while pasting temperature ranged from 70.94 to 81.21°C. All pasting parameters decreased with an increase in the level of protein substitution except pasting time and temperature that increased with the level of substitution. The sensory panelists rated the products highly for all the parameters investigated. Products MSG5 (70%M; 25%S; 5%G), PSG5 (70%P; 25%S; 5%G) and CSG5 (70%C; 25%S; 5%G) showed no significant difference (p≥0.05) in their acceptability to consumers and were thus the most preferred samples. The study showed that an acceptable gruel can be produced from yellow cassava or sweet potato starches with the addition of defatted soybean and groundnut flour at 25% and 5% substitution levels respectively.