Effect of Baking Temperature on the Phenolic Content and Antioxidant Activity of Black Corn (Zea mays L.) Bread

Black corn is known for its health-promoting properties, which are due to its high content of bioactive phytonutrients. However, the high temperatures required during the processing of bakery products usually trigger thermal degradation, and therefore, the loss of all labile bioactive compounds. In the present study, we evaluated the effect of baking temperature on the phenolic content (i.e., TPC, TAC and individual phenolics) and antioxidant activity in black corn (Millo corvo variety) bread. As a result, baking always resulted in a general decrease in TPC, even at 150 degrees C. In contrast, TAC only decreased when temperatures as high as 180 degrees C were applied. Some relevant individual phenolics were preserved during the whole process as long as 150 degrees C was used. In particular, the content of the major anthocyanin, namely, cyanidin-3-O-glucoside, hardly decreased from the raw flour to the final bread. The loss of antioxidant activity of Millo corvo raw flour during bread baking was avoided by heating at 150 degrees C. These results demonstrate the appropriate temperature to bake Millo corvo corn bread without losing the antioxidant characteristics and health-promoting properties of the starting black corn.