Quality of wheat bread enriched with onion extract and polyphenols content and antioxidant activity changes during bread storage

We determined the effect of onion skin extract (OE) on the quality of wheat bread: contents of total polyphenols and flavonols, antioxidative activity and their changes during storage. With increasing doses of OE to bread, contents of total polyphenols and flavonols and the antioxidative activity were observed to increase. A higher total flavonol content was found in bread with 1% OE stored at 24 °C than in bread stored at 4 °C. There was no such relationship in the bread with 0.5% OE. Changes in flavonols content during storage for 72 h were insignificant. No clear trends of change in the antioxidant activity could be found at storage of breads. The addition of OE caused no changes in the yield and volume of bread and contributed to a decreasing value of L* parameter and to increasing values of ΔE, a* and b* parameters of bread crumb colour. Consumers accepted the smell and taste of bread with the addition of OE to a lesser extent than the control bread. Bread with 1% OE the taste was rated very low. Consumers rated the taste of bread with 1% OE low because it was bitter. Breads enriched with OE had a proper external appearance as well as crumb and crust features. Roasted onion aroma and taste were perceptible in the obtained breads. A bitterness was perceptible in breads baked with the addition of 1% of OE.