Effect of seed moisture content on flaxseed (Linum usitatissimum L.) milling and milled product characteristics

BACKGROUND: Research was conducted to determine the effect of seed moisture content on flaxseed milling and milled product characteristics. Flaxseed with 55,80,and 105 g kg(-1) moisture contents were milled on a centrifugal cutting mill (CCM) configured with a 0.475 and 9.5 kg min(-1) feed rate; a hammer mill configured with a blunt hammer face, 0.35 kg min(-1) feed rate, 3.1 mm screen, and 2,795 m min(-1) hammer tip speed; and a hammer mill configured with a sharp hammer face, 0.35 kg min(-1) feed rate, 2.7 mm screen, and 3,870 m min(-1) hammer tip speed. RESULTS: Fine-particle fraction (<= 600 mu m) yield was greater from flaxseed with 55 than with 105 g kg(-1) moisture content. Surface lipid content correlated positively with fine-particle yield (r = 0.82, P = 0.01). At each moisture level, the surface lipid extracted from the fine-particle fraction was greater with 9.5 than 0.475 kg min(-1) configuration of CCM and tended to be greater with the blunt than with the sharp hammer configuration of the hammer mill. CONCLUSION: Results indicated that flaxseed was more difficult to mill to a fine particle size at high than at low moisture content regardless of the mill configuration. Enhanced lipid oxidation was not detected in freshly milled flaxseed. (C) 2009 Society of Chemical Industry