Enrichment of a local sourdough bread with zinc and selenium through the use of biofortified whole wheat flour

Within the scope of this study, the possibilities of enriching the flour used in the production of a local bread with biofortified whole grain flour in order to eliminate the deficiency of zinc (Zn) and selenium (Se) microelements were investigated. For this purpose, the biofortified whole wheat flour was substituted into the control flour used in local bread at rates of 25, 50, 75, and 100%. The technological, gluten, and dough quality properties of the substituted flours were revealed. In the study, breads were baked using two sourdough and commercial yeast combinations in the substituted flour samples. The selenium and zinc contents and nutritional and physicochemical properties of breads and substituted flours were determined, and the effectiveness of enrichment compared to the control was evaluated. As the substitution rate increased, the zinc and selenium contents of the flours increased, but the properties related to gluten quality were negatively affected. As the substitution rate increased, the Zn and Se contents of the breads also increased, and all substitution rates were statistically different from each other. The Zn contents of the bread samples ranged from 10,29 to 44,02 mg/kg, and the Se contents ranged from 51,6 to 235,1 μg/kg. The Se content of the yeast combination A, in which sourdough was used more, was found to be statistically higher than the B combination. For the 75% replacement rate, the RDA zinc value was 33,2% and the RDA selenium value was 36,0% in the breads. As the substitution rate increased, the total phenolic content, antioxidant activity, and protein content of the biofortified breads increased. The volume values of biofortified breads varied from 395,0 to 525,0 ml. In general, as the substitution rates increased, the L* and a* values in the bread crust decreased, while the L* value decreased and the a* and b* values increased in the crumb. On the other hand, as the substitution rate increased, the hardness value increased. It has been observed that gluten formation occurs in breads with a substitution rate of up to 50%. As the rate of substitution increased, sensory evaluation scores decreased in general. It was noteworthy that some of the sensory evaluation scores of the breads with a 25% substitution rate were close to the control bread. These results have shown that making local bread from flours enriched with biofortified whole wheat flours will make significant contributions to eliminating the deficiency of selenium and zinc microelements.