Abstract
Mature soybean seeds (var. Kyûshû No. 12) were fractionated into the 3 parts (Cotyledon, Hull, and Hypocotyl) and analyzed (Table 1). As the free sugars, only glucose was detected as the monosaccharide, and sucrose, raffinose, stachyose, and verbascose were determined in the three parts (Table 2). It was found that all of the three parts contained 0.2-0.4% of cold-water soluble polysaccharide, whose component sugars were galactose, glucose, mannose, arabinose, and xylose (Table 3). The hull contained 33.5% crude fiber (93% α-cellulose), while the cotyledon and hypocotyl contained about 2% crude fiber consisting of α-, β-, and γ-celluloses (Table 4). Even α-cellulose showed the presence of galactose, arabinose, mannose, and xylose besides glucose after hydrolysis, while β-cellulose consisted mainly of galactose and arabinose (Table 5). The hull contained only 0.01% starch, while the other two parts contained about 0.3% starch, as determined by enzymatic and colorimetric methods (Table 6). The hull and hypocotyl contained 3-4% pectic substance, while cotyledon contained only 1%. After hydrolysis these pectic substances gave not only galacturonic acid, galactose, and arabinose, but also fucose, xylose, and mannose in varying ratios according to the part of the seed (Table 7). Thus the methods for analyzing soybean carbohydrates have not yet been established.
