EVALUATION OF POUNDED YAM PRODUCED FROM YELLOW YAM (Dioscorea cayenensis) FLOUR

Abstract

Yellow yams (Dioscorea cayenensis) are eaten mostly as boiled, fried, roasted and pounded yam. This study was aimed at determining the chemical, pasting, functional and organoleptic properties of pounded yam flour produced from Dioscorea cayenensis to establish its suitability for production of pounded yam flour. It was peeled, washed, sliced to 2, 4 and 6 mm thickness, blanched at temperature of 90 and 100 ° C for 10, 15 and 20 minutes, drained, dried using hot air oven at 65 ° C and the dried chips were milled, sieved and packaged. Dioscorea rotundata was used as control. They were analysed based on physicochemical, functional, pasting, minerals and organoleptic properties. All data obtained were subjected to statistical analysis. The result of the study showed that pounded yam produced from yellow yam Dioscorea cayenensis flour had highest values in all parameters; protein content of 5.92%, fibre content of 3.30%, ash content of 3.07%, carbohydrate of 89.23%, pH of 6.47, total carotenoids concentration of 0.31 (mg / 100g), total titratable acidity of 0.69%, total soluble solids of 2.07, amylose of 24.29%, amylopectin of 69.76%, solubility of 13.63 % at 30 o C, 13.63% at 60 o C and 15.27% at 90 o C, swelling power of 87.02% at 30 o C, 91.29% at 60 o C and 90.31% at 90 o C, gelation capacity of 1.33, emulsification capacity of 36.42%, oil absorption capacity 2.18 (g/ml), water absorption capacity 2.89 (g/ml), bulk density of 0.54 (g/cm3), swelling index of 2.83 (g/ml), peak viscosity of 199.92 (RVU), trough 1 of 183.42 (RVU), breakdown of 24.50 (RVU), final viscosity of 324.08 (RVU), setback of 140.67 (RVU), pasting temperature of 85.60 (° C), peak time of 7.00 (min), sodium of 1.35 (mg /100 g), potassium of 4.48 (mg /100 g), magnesium of 0.21 (mg /100 g), zinc 0.04 (mg /100 g), calcium of 0.50 (mg /100 g), iron 0.10 (mg /100 g), copper of 0.04 (mg /100 g), phosphorus of 1.05 (mg /100 g), lead of 0.01 (mg /100 g) respectively, except in fat, dispersibility and organoleptic properties. It indicates that, Dioscorea cayenensis has good qualities than Dioscorea rotundata when processed to pounded yam flour, though, the acceptability of the product from organoleptic point of view which is subjective, is less when compare with the control, because it is a new product, it was less attractive to the consumer. Therefore, based on physicochemical, functional, pasting and organoleptic properties, pounded yam flour of 4 mm at 100 o C for 10 minutes is recommended for pounded yam flour produced from yellow yam and also further works should be done to improve on the organoleptic properties of pounded yam produced from yellow yam Dioscorea cayenensis flour to enhance its utilization