Arabinoxylans from rye and wheat seed that interact with ice.

Arabinoxylans that interfere with growth of ice crystals have been purified from rye (Secale cereale L., Rosen) and two varieties of wheat (Triticum aestivum L., Genesee and Hillsdale) seed. The most active polysaccharide from each seed type was homogeneous in the sense that all the molecules were in the same size range, they contained the same sugar residues, and they reacted similarly in chemical characterization experiments. Structural studies showed that the polysaccharides consist of a xylan chain to which are attached side-chains that contain a single, terminal arabinose residue. The polysaccharides differ with respect to the number of arabinose residues. The xylose:arabinose ratios in the most active fractions from rye, Genesee wheat, and Hillsdale wheat are 1.26, 1.54, and 2.08, respectively. Gel-permeation column chromatography showed that the most active polysaccharide from each seed type has a molecular weight greater than 2 x 10(6) and that the rye polysaccharide is slightly larger than the Hillsdale wheat polysaccharide. The rye polysaccharide is a better inhibitor of ice-crystal growth than is the Hillsdale wheat polysaccharide.