Background: Buckwheat, despite its broad nutritional benefits, is still not widely appreciated grain. It contains a protein with preferred amino acid composition and it is a valuable source of micronutrients and vitamins of the B group and vitamin E. Moreover, buckwheat groats have a high amount of polyphenols, including flavonoids and flavones. Eating rye bread is beneficial due to its high content of dietary fiber, phenolic acids and characteristic taste and aroma. Therefore, the use of rye flour and buckwheat mill products for bread may allow obtaining a product of high nutritional value and flavor.
Objective: The aim of the study was to evaluate the influence of buckwheat products addition and baking process on the antioxidant properties of rye-buckwheat blends and breads.
Material and methods: Experimental material was rye flour type 580 and buckwheat flour, wholegrain flour and bran obtained by grinding buckwheat groats. Buckwheat products share was 20 and 35%. The control was the rye flour. In the rye-buckwheat blends and bread loaves, the contents of selected flavonoids by HPLC method, total polyphenols content by Folin-Ciocalteu method and the antioxidant activity by the DPPH˙ radical scavenging method were determined.
Results: Buckwheat bran was significantly richer in total polyphenols, rutin, quercetin, orientin and isoorientin than other buckwheat products and rye flour. Bread after baking contained similar amount of total polyphenols and quercetin and have a comparable ability to scavenge 1,1-diphenyl-2-picrylhydrazyl radicals (DPPH˙) than the corresponding blends. Baking process negatively affected the amount of rutin, orientin and isoorientin.
Conclusions: The use of buckwheat bran as a replacement for wheat flour in bread significantly increases its nutritional value. The process of baking unequally affects the content of particular groups of antioxidant compounds.