Phenolic compound content and antioxidant activity of hydro-ethanolic extracts of durum wheat bran (Triticum turgidum subsp. Durum) of some Algerian varieties

Abstract

The aim of this study is to evaluate the content of durum wheat bran (DWB) of three Algerian varieties in secondary metabolisms such as total phenols, flavonoids and condensed tannins, and to determine their antioxidant power. The experiment was carried out on the following three varieties of durum wheat (Triticum turgidum subsp. Durum): Siméto, Chen’s and Vitron. The maceration of the wheat bran powder was realized with 80% ethanol. The determination of total phenols was carried out by the folin-ciocalteu method, that of flavonoids by the aluminum trichloride and sodium hydroxide process and condensed tannins by the vanillin method. Antioxidant activity was tested by four methods: free radical scavenging with DPPH, FRAP (Ferric Reducing Antioxidant Power) test, β-carotene bleaching test and the ferrous ion chelating effect (FIC). The total phenol contents (TPC) for the Siméto, Chen’s and Vitron varieties are respectively: 1.678±0.051 mg AGE/g DWB, 1.817±0.231 mg AGE/g DWB and 1.813±0.075 mg AGE/g DWB. The concentration of flavonoids (TFC) is: 0.543±0.102 mg CE/g DWB (Siméto), 0.594±0.116 mg CE/g (Chen’s) DWB and 0.503±0.077 mg CE/g DWB for Vitron. The content of condensed tannins (CTC) is 1.526±0.193 mg CE/g DWB for siméto, 1.345±0.850 mg CE/g DWB for chen’s and 1.587±0.182 mg CE/g DWB for vitron. The antioxidant activity revealed that the antioxidant power with DPPH and FRAP test is less important compared to the bleaching of β-carotene and the chelating effect of ferrous ions (FIC) which gives the same percentage of activity as the standard. This study demonstrates the richness of durum wheat bran in phenolic compounds and antioxidant substances.