Antioxidant Activity, Technological and Rheological Properties of Baked Rolls Containing Dried Onions (Allium cepa L.)

The aim of this study was to explore the effect of substituting wheat flour by 2.5, 5, 10 and 20% white, yellow and red dried onion. It caused improvement in antioxidant potential and increasing concentrations of total phenolic compounds from 1.52 to 3.81 mg GAE/g d.w., decrease of loaf volume (from 520.97 to 202.88), also a change of crumb color and increase of hardness, gumminess and chewiness. The increase of the content of red onion powder caused reduction in the lightness (from 69.50 to 55.37) and increase in the redness (from 0.23 to 4.21). The best loaf volume was demonstrated by rolls, in which wheat flour was replaced with 2.5% of dried onion (399.37, 433.23, 390.03 cm3/100 g white, yellow and red, respectively). The results of sensory evaluation suggest that rolls, in which 5% of the flour was replaced by dried onions, showed the highest value of the “general acceptance”. Practical Applications Powdered dried onion is a material that contains active substances such as antioxidants and volatile sulfur compounds. Baked rolls are enjoyed by consumers all over the world. In this study, onion powder obtained from white, yellow and red onion cultivars was utilized in substituting wheat flour in baked rolls. The result showed that wheat flour could be substituted by 5% of onion powder without adverse effect on the consumer acceptability, loaf volume, crumb color and texture of the bread produced. Furthermore such rolls characterized by improved antioxidant properties due to increasing concentrations of total phenolic compounds.