Biologically active phenolic compounds in buckwheat, oats and winter spelt wheat

Abstract

The current study was aimed to determine the total phenolic content and antioxidant activity, rutin, quercetin and phenolic acids content in buckwheat, husked and common oats, winter spelt, winter and spring wheat grain with and without husks or glume, only husks or glume as well as to estimate phenolic compounds ratio and to compare their distribution between cereal grain and husks or glume. In this way to ascertain the losses of phenolic compounds in grain which will be used for food production. Total phenolic content and antioxidant activity were determined using the spectrophotometric method and individual phenolic compounds were estimated by high performance liquid chromatography. The significantly highest total phenolic content (10.2 ± 1.6 mg g -1 dry weight (d.w.) in grain with husks and 14.1 ± 2.0 mg g -1 d.w. in husks), antioxidant activity (2–4 times), rutin concentration (from 146.5 to 406.3 µg g -1 d.w.) and with a few exceptions hydroxybenzoic acids concentrations of all group of cereal samples (grain with and without husks or glume and only husks or glume) were established for buckwheat. Oats grain without husks or only husks were distinguished by the highest quercetin content, which was higher in husked oats samples (31–89 µg g -1 d.w.). The highest total phenolic acids content was in common oats husks (882.4 µg g -1 d.w.). Ferulic and p-coumaric acid significantly (P < 0.01) predominated in all oats and wheat samples and accounted for about 70–90% of the total phenolic acids content. Syringic acid is characteristic of oats, winter spelt and winter wheat grain without glume and only glume. In all group of cereal samples sinapic acid predominated only in cereal grain with and without husks or glume. Significantly (P < 0.05) higher concentrations of vanillic, p-hydroxybenzoic, 3,4-dihydroxybenzoic, p-coumaric, ferulic acids, total phenolic content, antioxidant activity were quantified in cereal husks or glume compared with those in grain with and without husks or glume.