Abstract
In this study, we evaluated the effect of onion peel extract (OPE), which is rich in phenolics and flavonoids, on the performance of high-gluten wheat flour and bread quality to meet consumer demand for functional bakery products. The addition levels of OPE were set at 0%, 0.25%, 0.5%, 0.75% and 1% (w/w), respectively, to analyze their effects on water/oil absorption capacity, falling number, and rheological properties (farinographic properties, tensile properties, dynamic rheological properties and gelatinization characteristics) of dough, as well as bread quality (antioxidant activity, texture, microstructure, specific volume and sensory evaluation). When the OPE addition level was 0.25% and 0.5%, the dough's oil absorption capacity, farinographic properties, tensile properties, dynamic rheological properties, and gelatinization characteristics were all improved. Correspondingly, a more compact and ordered microstructure was observed in the dough. It was found that total phenolic content, total flavonoid content, and antioxidant capacity of bread significantly increased with the increase in the OPE addition level (p < 0.05). The texture analysis of the bread showed that the addition of OPE reduces the hardness and chewiness of bread, indicating that the texture of bread was easily accepted by consumers. In the sensory evaluation, when the addition level of OPE was 0.5%, the color and flavor of bread were improved, and the overall acceptability was relatively high. In conclusion, OPE has improved the texture characteristics and nutritional value of bread. It is recommended that the addition level of OPE in high-gluten wheat flour dough and bread be below 0.5%.