The Effect of Adding Flour Soy and Lentil to Doughnut on its Physicochemical Properties

Doughnut is a sweet fried golden-brown snack with energy value that is served as a convenient food. Quality of fried doughnut depends on its appearance (color, shape and brightness), aroma, flavor and nutrition value. In this research the effect of wheat flour partial replacement with soy flour and lentil flour (0, 15 and 30%) on physicochemical characteristics of doughnut including oil uptake, moisture loss, volume, texture, color and porosity were evaluated. Finally, sensory evaluation to determine the effects of soy and lentil on consumer acceptance of donuts was performed. The results were showed that addition of soy and lentil flour caused a decrease in moisture loss, fat content, volume, porosity and lightness of doughnut. During frying (a*) of doghnut shift to positive values and soy protein aggravate it. Crust color wasdarkenedprogressively with increasing frying time. The hardness of doughnuts decreased with increasing soy level but other rheological parameters did not change significantly. Increasing lentil flour, because of forming strong covalent bonds, increased this parameter. Sensory evaluation results showed that the sample contain 15% soy flour was the highest overall acceptability.