Phenolic contents and antioxidant activities in covered whole-grain flours of Norwegian barley varieties and in fractions obtained after pearling

作者：Holtekjolen Ann Katrin^*; Sahlstrom Stefan; Knutsen Svein Halvor

来源：Acta Agriculturae Scandinavica Section B-Soil and Plant Science, 2011, 61(1): 67-74.

DOI：10.1080/09064710903496527

• Co-product
• Folin-Ciocalteu's method
• FRAP
• total phenolic content

Phenolic contents and corresponding antioxidant activities were studied in covered whole-grain flours of Norwegian barley varieties and in two different pearling fractions. In covered whole-grain flours the summarized amount of phenolics (Sigma-P) ranged from 481-676 mg gallic acid equivalent (GAE)/100 g dry matter (DM) and the corresponding total antioxidant activities (Sigma-FRAP) between 6.1-8.7 mmol Fe3+/100 g DM. About 50% of the phenolics in these samples were easily extractable (free). Upon pearling a general decrease in both Sigma-P and Sigma-FRAP was seen in the pearled samples, while the ratio between free and bound phenolics was similar or increased to those in the covered whole-grain samples. The hulls had the highest Sigma-P and Sigma-FRAP and were dominated by bound phenolics. Despite accounting for only 10-20% of the total grain weight, the hulls typically contributed to 45% of the total antioxidant capacity measured in the covered whole-grain flours. Pearling makes it possible to obtain barley fractions with different amounts of phenolics, different ratios of free and bound phenolics, and thus different antioxidant activities.

• 出版日期2011