Non-Starch polysaccharides of seeds of soybean [Glycine Max. (L)]

Mature soybean seeds (variety FFR 559) were analysed for the non-starch polysaccharide composition. Non-starch polysaccharide (NSP) fractions were extracted by two methods, namely, chemical (triehloroacetic acid-TCA) and enzymatic methods. Yields of TCA- soluble, enzyme-soluble, TCA-insoluble and enzyme-insoluble NSP were 1.4, 13.1. 24.9 and 28.8% of the defatted flour, respectively. The differences in yields between the two methods were primarily due to contamination with non-carbohydrate materials (protein, ash and lignin) to the extent of 18.4- 30.8%. The results showed the soluble NSP to be an arabinogalactan type of polysaccharide containing arabinose and galactose in approximately 2:l ratio, and a uronic acid content of 30.4%. Cellulose associated with arabinogalactan, xylan and pectic polymers predominate the insoluble NSP. Mature soybean seeds were found to be free of starch.