Influence of breadmaking on antioxidant capacity of gluten free breads based on rice and buckwheat flours

In the present study new formulations for gluten-free bread based on mixtures of rice (RF) and buckwheat flour (light buckwheat flour (LBF) or wholegrain flour (WBF)), in the proportions of 90:10, 80:20, and 70:30 were made. The gluten-free breads were investigated for their total phenolic content, rutin and quercetin contents, antioxidant activity (AIDA) by beta-carotene bleaching method, reducing power, scavenging activity on 1,1-diphenyl-2-picrylhydrazyl (DPPH center dot) radicals, and chelating activity on Fe2+. The increased amount of LBF or WBF in the dough formulation resulted in the final products with higher antioxidant properties. Baking treatment expressed different influences on antioxidative properties of the final gluten-free product in terms of raw materials, applied recipe and antioxidative capacity in comparison to calculated values based on raw materials. Final gluten-free products were characterized by lower total phenolic and rutin contents, lower antioxidative and reducing activity and on the other hand higher DPPH and chelating activity as well as quercetin content in comparison to calculated values. Bread containing wholegrain buckwheat flour expressed in most of the cases higher values of measured antioxidative parameters than bread prepared with light buckwheat flour and thus contributes to their additional functional property. (C) 2011 Elsevier Ltd. All rights reserved.