The aromas generated in wheat flour or wheat starch extruded with or without the addition of cysteine and reducing sugars (0·044 mol/kg feed) were evaluated by descriptive sensory profiling. A trained sensory panel (n=9) developed a consensus vocabulary of 24 attributes, of which 17 varied significantly (P<0·05) between the samples in analysis of variance (ANOVA). The extrudates were characterised by four loading domains in principal component analysis (PCA). Biscuity, cornflakes, sweet and cooked milk were discriminative for extruded flour. Addition of cysteine and glucose resulted in stronger popcorn, nutty/roasted and puffed wheat aromas. Savoury and sulphur notes were more evident in the flour-cysteine extrudate when glucose was replaced by xylose. In starch extrudates modified by the addition of cysteine and sugar, the more objectionable attributes, sharp/acidic, stale cooking oil, cooked apple and wet washing, became dominant. Flour appeared to contain important aroma precursors not present in starch.