Variation in the composition of water-soluble polysaccharides in flaxseed.

Abstract

One hundred and nine accessions of flaxseed (Linum usitatissimum L.) from twelve geographical regions and including oil, fiber, and brown- and yellow-seeded types were used to determine the composition of water-soluble polysaccharides, total carbohydrates, protein, and oil. The content of water-soluble polysaccharides ranged from 3.6 to 8.0%. Neutral monosaccharides of the water-soluble polysaccharide fraction consisted mainly of glucose, xylose, galactose, and rhamnose. The latter varied 3-fold from 8 to 24% of total monosaccharides, although 92% of the accessions had rhamnose values between 10 and 20%. Fucose was a minor component of the water-soluble polysaccharide fraction and displayed the highest coefficient of variation. Xylose was the second largest carbohydrate component, and its mean values were highly correlated with cumulative frequency. Variation of galactose content of the water-soluble polysaccharide fraction of flaxseed from all accessions was normally distributed. Glucose concentration ranged from 21 to 40% and represented the major neutral monosaccharide in flaxseed. The ratio of rhamnose to xylose, an indication of the ratio of acidic to neutral polysaccharides, ranged from 0.3 to 2.2. Carbohydrate yield and sugar contents of the water-soluble polysaccharide fraction of flaxseed accessions were independent of protein and oil content. Flaxseed accessions, when grouped by geographical region or type, can be differentiated by principal component analysis.