Evaluation of antioxidant activities and total phenolic contents of typical malting barley varieties

Fourteen typical malting barley varieties from China were evaluated for their DPPH radical, ABTS radical cation and superoxide anion radical scavenging activities, reducing power, metal chelating activities, and total phenolic contents (TPC). All barley samples exhibited significant antioxidant activities determined by different assays, and contained significant levels of phenolic compounds. Gan4 and Wupi1 barley exhibited the highest DPPH radical scavenging activity, ABTS radical cation scavenging activity and reducing power. Gan4 and Humai16 barley showed the highest TPC, whereas the highest superoxide anion radical scavenging activity and metal chelating activity were found in Huaimai19 and Ken3 barley, respectively. The Pearson correlation analysis revealed that the TPC showed strong correlations with DPPH radical scavenging activity, ABTS radical cation scavenging activity, and reducing power (P < 0.01), whereas its correlations with superoxide anion radical scavenging activity and metal chelating activity were poor (P > 0.05). Moreover, DPPH radical scavenging activity, ABTS radical cation scavenging activity and reducing power were well positively correlated with each other (P < 0.01). Principal component analysis (PCA) was applied to understand the interrelationships among the measured antioxidant activity evaluation indices, and to gain an overview of the similarities and differences among the 14 barley varieties.