(1.RAR.3),(1.RAR.4)-.BETA.-glucan and Bound Phenolics in Rolled Oats

Abstract

Rolled oats, a processed oat product, contain about 4 g of (1 -› 3),(1 -› 4)-β-glucan (β-glucan) per 100 g. It also contains 27.0 mg of ferulic acid and 3.5 mg of p-coumaric acid. Moreover, the presence of β-glucan, ferulic acid, and p-coumaric acid was confirmed in commercial food products with rolled oats in their lists of ingredients. The radical scavenging activity of a water-soluble polysaccharide fraction (WS) extracted from rolled oats was examined and components involved in this activity were evaluated. This WS exhibited radical scavenging activity and a strong correlation (r=0.9982) was observed between this activity in terms of the ferulic acid equivalent and WS sample concentration. Concerning the neutral sugar composition of the WS, glucose accounted for about 49 mol%, followed by xylose (about 28 mol%) and arabinose (about 15 mol%). In addition, ferulic acid was contained in a macromolecular fraction collected by gel-filtration chromatography of lichenase-treated WS. Therefore, arabinoxylan containing ferulic acid may be a component leading to the radical scavenging activity of the WS.