Yam (Dioscorea spp) flour fortification with protein of soybean flour

The objective of this study was to determine the effect of added soybean flour on some attributes of the rehydrated mass prepared from the mixture of soybean and yam flours. Fortifying fufu (or iyan), a food made from yam tubers, is a potential means of improving the nutritional level of certain African people. The yam flour prepared by freeze drying had 1.25% protein; the commercial soybean flour, 53.15%. Samples prepared from a yam-soybean flour mixture were softer and more tacky when compared to samples prepared from yam flour. Reducing the proportion of rehydration water in samples which contained soybean flour produced samples that had a texture similar to that of the control samples. Samples were similar in texture when the following proportion of water was added: to one part yam flour (control treatment), three parts water; to yam-soybean flour mixture with 5% protein, 2.5 parts water; and to yam-soybean flour mixture with 10% protein, 2 parts water. The presence of soybean flour in the rehydrated mass made it darker, less red, and more yellow when compared to the control treatment. A panel of ten university students from West Africa, who were familiar with the yam food, evaluated samples made from yam flour, and yam and soybean flours of 5 and 10% protein levels. These samples were prepared by reducing the proportion of water to the dry mixture as the amount of soybean flour was increased. The panel did not prefer one sample over another. All samples received scores on a six-point scale that placed them slightly higher than the liked moderately category. This study shows that fufu (or iyan) can be fortified with protein from soybean flour to at least 10% protein without changing certain quality attributes so as to cause a panel to show a preference among samples.