In vitro anti-oxidant activity of xylo-oligosaccharides derived from cereal and millet brans - A comparative study

Xylo-oligosaccharides (XO) were obtained from the respective WUP (water unextractable polysaccharides) of rice, ragi, wheat and maize brans by the xylanase action in 3.31%, 15.60%, 40.00% and 9.33% yields, respectively. Sugar composition of XO mixtures as analysed by GLC indicated arabinose:xylose in a relative ratio of 3.6:1; 1:2.43; 1:5.13 and 1:1.25 for rice, ragi, wheat and maize, respectively. The presence of phenolic acids in xylo-oligosaccharide mixtures was ascertained by high-performance liquid chromatography (HPLC) on C-18 column. Antioxidant activity of the xylo-oligosaccharide mixtures was carried out by three different methods that is (a) 1,1-di phenyl-2 picryl-hydrazyl (DPPH), (b) beta-carotene emulsion and (c) ferric reducing anti-oxidant power (FRAP) assays. XO mixture of ragi exhibited relatively higher antioxidant activity compared to the XOs of rice, wheat and maize by DPPH and FRAP assays. (C) 2010 Elsevier Ltd. All rights reserved.