Soluble free phenolic compound contents and antioxidant capacity of bread and durum wheat genotypes

Abstract

The objective of this study was to determine phenolic compounds and the total antioxidant capacity in the grain of ten bread (T. aestivum L.) and ten durum (T. durum Desf.) wheat genotypes. Soluble free forms of total phenolics, flavonoids, PVPP (polyvinylpolypyrrolidone) bound phenolics, proanthocyanidins and phenolic acids were investigated. In addition, the correlation coefficients between total antioxidant capacities and the concentration of different soluble free phenolic compounds, as well as between soluble free total phenolics and phenolic acids, flavonoids and PVPP bound phenolics were determined. Significant differences in the content of aceton/water extractable total phenolics, PVPP bound phenolics and phenolic acids between and within two wheat species were found. On the average, durum wheat samples had about 1.19-fold higher total phenolic compounds and about 1.5-fold higher PVPP bound phenolics than bread wheat samples. Three phenolic acids, ferulic, caffeic and chlorogenic, were detected in wholemeal bread wheat. Caffeic acid was not found in durum wheat samples whilst ferulic acid was the most abundant. Proanthocyanidins in bread and durum wheat genotypes were not detected. The antioxidant capacity measured as the DPPH radical scavenging activity was similar in wholemeal of bread and durum wheat, however, significant differences were observed among genotypes within species.