The Effect of Black Cumin Seed (Nigella sativa) Meal on Physicochemical, Textural and Sensorial Properties of Sponge Cake

Black cumin seed meal, a by- product of oil extraction, contains high levels of nutritional proteins, as well as desirable compounds such as antioxidants and fiber. In this research work, the effects of replacing wheat flour with black cumin seed (Nigella sativa) meal at the levels of 0, 5, 15 and 15% on the physical, chemical and sensory characteristics of sponge cake were investigated. The chemical analysis of black cumin seed meal showed that it had high content of protein (40%) and fiber (10%), so that increasing the level of black cumin seed meal from 0 to 15% in the formulation of sponge cake resulted in a significant (p<0.05) increase in the protein and fiber content of the samples. Addition of black cumin seed meal significantly decreased the content of moisture in the cake samples while significantly increased the fat and ash content and did not change the pH values of the cake samples significantly (p<0.05). Upon increasing the level of meal in the formulation, the volume and density indices of the samples decreased and increased, respectively. The color indices of L*, a*and b* of meal incorporated cake samples decreased, comparing to those of control sample (0% of meal). The results of texture analysis showed that increasing the levels of black cumin seed meal from 0 to 15% in the formulation, reduced (p<0.05) the firmness of cake samples. Finally, the results of physicochemical and sensory analyses of the cake samples showed that addition of black cumin seed meal at the level of 10% was the most appropriate amount for enrichment of sponge cake and thus formulating a functional product, since undesirable changes in the mentioned properties of the samples were detected upon addition of higher amount of meal.