Investigation of the opportunities of usage in bread making with the antioxidant activity of onion shell powder

In this study, red (Pusa Red) and yellow (Arka Pitamber) onion peels, which are obtained from Iskenderun, Antakya and Adana vegetable markets and which are the most grown onion species in Turkey (Allium cepa L.), were dried and powdered. Onion peel powder (OPP) was substituted with wheat flour at 2%, 4%, and 6% ratios, and bread was produced with the standard method. Total phenolic substance, anthocyanin, DPPH antioxidant activity, crude fiber, moisture and bread color (L*, a*, b*), volume, pore structure, base diameter, height, dough and bread yield, baking in OPP added wheat flour and breads cooking loss and sensory evaluation analyzes were performed. It has been determined that the addition of OPP generally contributes positively to improving bread qualities. In particular, the addition of 6% yellow onion peel powder (YOPP) increased the total DPPH antioxidant activity of the bread approximately 4 times, and the addition of 6% red onion peel powder (ROPP) increased 6 times compared to the control bread. Total phenolic substance, anthocyanin substance, crude fiber content, dough and bread yield increased depending on the OPP addition rate. The difference in the height values of the breads is in the form of a significant decrease in the breads with the addition of ROPP. The addition of OPP created a significant difference (p<0.05) on both crust and inner color of the breads. It was concluded that likable bread was produced with the addition of OPP up to 4%, and at the level of 6%, the acceptability of the breads in terms of all these properties was negatively affected.