A pentose-rich hydrolysate fraction obtained by extraction of steam-pretreated sugarcane bagasse was analysed with regard to dissolved phenolics. The liquid obtained after steam pretreatment (2% SO2 (w/w) at 190 degrees C for 5 min) was divided into two parts: one containing dissolved compounds originating from hemicellulose (with xylose as the dominating compound), and the other containing predominantly dissolved compounds originating from lignin. Using nuclear magnetic resonance, the main dissolved compounds originating from lignin were identified as the glycosylated aromatics, 5-O-(trans-feruloyl)-L-Arabinofuranose and 5-O-(trans-coumaroyl)-L-Arabinofuranose, together with p-coumaric acid and small amounts of more common free phenolics such as p-hydroxybenzaldehyde, p-hydroxybenzoic acid and vanillin. The phenolic compounds were analysed and quantified using reversed-phase high-performance liquid chromatography. The findings show that SO2 steam explosion opened up new degradation pathways during lignin degradation. Copyright (c) 2012 Society of Chemical Industry