Effect of blanching period and drying temperature on selected physicochemical properties of cocoyam (Xanthosoma sagittifolium) flour

Abstract

This study investigated the influence of Blanching Time (BT) and Drying Temperature (DT) on some selected physico-chemical properties of cocoyam flour including water absorption capacity, bulk density, swelling index, wettability and gelatinization point. The quality parameters of the flour were analysed using AOAC standard methods and procedures. Twofactors, 3-levels Historical Data Design of Response Surface Methodology was adopted for the analysis to determine the effects of BT and DT on the investigated parameters. Second order polynomial model was obtained at 5% level of significance. The flour samples had 1.60 to 4.00% water absorption capacity, 0.71 to 0.81 g/cm3 bulk density, 5.2 to 6.8 g/g swelling index, 7 to 16s wettability and 68 to 90 oC gelatinization point. Samples dried at 60oC and blanched for 9.05 mins had better quality with optimum response values of 3.37% water absorption capacity, 0.76 g/cm3 bulk density, 6.22 g/g swelling index, 12.71 s wettability, and 85.73oC gelatinization temperature. BT and DT had significant effects on water absorption and wettability while no significant influence was observed on the bulk density, swelling index and gelatinization temperature of the flour at p ≤ 0.05. These findings will serve as a guide in ensuring proper choice of blanching time and drying temperature based on end-use and desired physico-chemical properties of cocoyam flour.