Free and Bound Phenolic Acids and Total Phenolics in Black, Blue, and Yellow Barley and Their Contribution to Free Radical Scavenging Capacity

Barley is considered a healthy food because of its high content of P-glucan and phenolic antioxidants. In the current study, 28 black, blue, and yellow barleys were investigated in terms of their composition of free and bound phenolic acids and 2,2-dipheny1-1-picrylhydrazyl radical scavenging capacity. Free phenolics were based on aqueous methanol extraction, whereas bound phenolics were extracted following alkaline hydrolysis. Phenolics were then separated and quantified by liquid chromatography and the Folin-Ciocalteu method. Significant differences were observed between the three barley color groups, and within each color group a wide range of phenolics concentrations existed. Ferulic acid was the predominant phenolic acid in free and bound extracts, followed by p-coumaric acid in all the barleys investigated. Total phenols content and individual phenolic acids strongly correlated with free radical scavenging capacity of barley. Black and blue barley were found to be related and distinct from yellow barley. The results showed significant variations in phenolics among barleys, with a potential for the development of barley grains with high content of phenolic compounds as antioxidant potential.