Pasting Properties of Composite of Cassava and Wheat Flours

Abstract

Classification of cassava and wheat using only amylose content is not sufficient enough to predict starch viscosity for end product recommendation, hence this study aimed at characterizing and categorizing the pasting profile of composite flours from cassava-citrus and wheat-watermelon using Rapid Visco Analyzer (RVA) (used in confectionary products), dried cassava, citrus rind, wheat grain and watermelon rind were processed into flour by grinding. Cassava-citrus and wheat-watermelon flours were blended in the ratio of 100:0, 25:75, 50:50 and 75:25 and labeled as AB1, AB2, AB3, AB4 and BC1, BC2, BC3, BC4 respectively. The data obtained from the pasting properties of composite cassava-citrus and wheat-watermelon flours are as follows: range of peak viscosity (249.6-446.0) and (97.1-116.3) RVU, trough value (158.5-251.5) and (59.5- 70.3) RVU, breakdown viscosity (91.1-184.1) and (37.6-46.0) RVU, final viscosity (222.3-509.3) and (184.4-214.2) RVU, setback viscosity (63.3-247.8) and (124.9-143.8) RVU, peak time (4.27-5.27) and (5.53- 5.67) min and pasting temperatures (72.45-73.40) and (90.40-91.25) oC. The pasting properties of wheat watermelon composite flours increased with increasing substitution of watermelon fibre while those of cassava citrus composite flours decreased with increasing substitution of citrus fibre until 50% replacement. Composite Cassava-citrus flour AB3 and wheat-watermelon flour BC1 respectively had the highest value for all the pasting properties evaluated. Hence, cassava-citrus flour AB3 with 50% citrus substitution and wheat-watermelon flour BC1 without any substitution could find applications in confectionery and pastry industries. Thus, the results also indicated that by incorporating citrus and watermelon fibre, it is possible to enhance the pasting properties of our local cassava and wheat flour. This will also serve as a way of converting wastes from citrus (citrus vesicles) and Watermelon rinds (Citrullus larnatus) into useful materials, thereby reducing environmental pollutions caused by these wastes.