Barley β-glucan extracts as rich sources of polyphenols and antioxidants

Barley β-glucan is a functional ingredient implicated to lower glycemic response, plasma cholesterol and food intake. The objective of the present study was to analyse the polyphenol content and antioxidant activities of four different solvent extracts of three barley β-glucan samples - Glucagel, Barley Balance (BB) and barley fibre rich fraction (BFRF). The polyphenol content and antioxidant activities of the β-glucans were in the order BFRF > BB > Glucagel (P < 0.05). Of the four different solvents used (70% acetone, 70% methanol, 70% ethanol and acidified methanol), 70% acetone gave the highest phenolic content (P < 0.05). The free radical scavenging capacities of 200 mg of BB and BFRF in 70% acetone were very similar to 40 μg of standard gallic acid, ferulic acid, ascorbic acid and trolox. We discuss the possibility that health benefits associated with β-glucan samples might depend on their polyphenol and antioxidant contents that vary with method of preparation and purity.