CHANGES IN POLYSACCHARIDE COMPONENTS AND METAL ADSORPTION ABILITY OF SOYBEAN DIETARY FIBER ON HEATING

Soybean dietary fiber consists of many kinds of polysaccharides which have different physiological effects on human, and its physiological f unction may be changed by heating. In this paper, the composition of p olysaccharides in cell wall and its changes by heating were described. High yield of crude polysaccharides was observed in roasted soybean, suggesting that high molecular weight compounds were produced by heati ng. On the other hand, as an increase of soluble hemicellulose and a d ecrease of insoluble hemicellulose were observed, low molecular weight compounds may be produced by heating. And also we found some differen ces in ion-adsorbing ability between raw and roasted soybean. Adsorpti on ability of aluminium ion by raw soybean soluble dietary fiber (SDF) was most remarkable. Adsorption of aluminium by pectic substance-1 an d 2 (hot water extract and 0.5% ammonium oxalate extract) and hemicell ulose-1 (1 N-sodium hydroxide extract) isolated from peeled soybean wa s observed. But pectic substance-1 and 2 isolated from soybean peel ha d lower adsorption ability than peeled soybean. Ail of those adsorptio n abilities were decreased by heating. Hemicellulose-2 (4 N-potassium hydroxide extract) and cellulose isolated from soybean had almost no a dsorption ability.