The effect of processing on functional compounds in buckwheat was investigated. Extractions of buckwheat flour were carried out before and after roasting or extrusion. Folin-Ciocalteu assays indicated that processing did not cause any change in total phenolic content in buckwheat flour. Roasted (200 degrees C, 10 min) dark buckwheat flour exhibited an increase in non-polar compounds as well as polar compounds whereas extrusion exhibited increase only in polar compounds. Antioxidant activity test (DPPH) showed that roasting at 200 degrees C for 10 min decreased the antioxidant activity slightly whereas extrusion (170 degrees C) did not cause any change. The results suggest that processing conditions can be optimized to retain the health promoting compounds in buckwheat products. (c) 2005 Elsevier Ltd. All rights reserved.