Simple cakes elaborated with flour of watermelon inner skin (Citrullus vulgaris, Sobral): chemical, physical, and sensory evaluation

The flour of watermelon inner skin was obtained, its composition was determined, and it was used in the cake formulation. Cakes without watermelon inner skin (control) and others containing 7 and 30% of watermelon inner skin(experimental), a non-wheat flour substitute, were elaborated. The chemical composition, physical, and physicochemical characteristics were evaluated. In the sensory evaluation, one hundred non-trained panelists were assigned blocks of four samples and performed sensorial tests using a nine point hedonic scale and multiple comparison. The obtained data were evaluated by descriptive statistics, ANOVA, and Tukey and Dunnet tests. The results revealed that 100 g of the watermelon inner skin flour contained 9,06 g of moisture, 12,72 g ashes, 0,7 g fats, 1,2 g proteins, 31,01 g insoluble fibers, 45,21 g total carbohydrates, and 192,75 kcal. The weight, height, and yield were higher and the diameter was greater in the experimental cakes, whereas the spreading factor and the apparent volume of the cake with 30% of watermelon inner skin flour were lower. The experimental cakes presented lower pH, higher titratable acidity, higher contents of fiber and moisture, lower contents of total carbohydrates, and reduced energetic value. The cakes presented good acceptance and more than 60% of the panelists would buy the cakes. The cake with 7% of watermelon inner skin flour was slightly better than the control and differed from the cake containing 30% of watermelon inner skin flour in aroma and flavor. Therefore, the use of watermelon inner skin flour for cake production, under the conditions of this research, is viable from the technological, nutritional, and sensorial point of view.