Soybean seeds contain many biologically active secondary metabolites, such as proteins, saponins, isoflavones, phytic acids, trypsin inhibitors and phytosterols. Among them, saponins in soybeans have attracted considerable interest because of their health benefits. Soyasaponin A and B are the most abundant types of saponins found in soybeans along with soyasapogenol (aglycone), which is a precursor of soyasaponin. The main purpose of this experiment was to determine the concentration of soyasapogenol in soybean seeds and sprouts as a function of seed size, usage, seed coat color and seed cotyledon color. The 79 Korean soybean varieties were cultivated at Yesan of Chungnam in 2006 for the analysis of soyasapogenol using HPLC with Evaporative Light Scattering Detection (ELSD). The total average concentration of soyasapogenol was 1313.52~mug~;g-1 in soybean seeds and 1377.22~mug~;g-1 in soybean sprouts. Soybean sprouts were about 5% higher than soybean seeds in average total soyasapogenol concentration. In the process of sprouting, the average soyasapogenol A content decreased by approximately 1.6%, but soyasapogenol B and total soyasapogenol increased by 8.31% and 4.88%, based on the content of soybean seeds. When classified according to the size of seeds, the total soyasapogenol concentration of soybean seeds were not significantly different (p<0.05) On average, small soybean seeds were increased by as much as 103.14~mug~;g-1 in sprouting process. As a function of the use of the seeds, The total soyasapogenol in soybean seeds were significantly different (p<0.05). While, the soybean sprouts were not significant different (p<0.05). Altogether, sprout soybean seeds show the greatest change in content during the germination process. When seeds with different coat colors were compared, the total soyasapogenol concentration of soybean with yellow seed coats (1357.30~mu g~;g1 ) was slightly higher than that of soybean with black (1260.30~mug~;g-1 ) or brown (1263.62~mug~;g-1 ) seed coats. For the color of the cotyledon, the total soyasapogenol concentration was significantly increased in green cotyledon during the germination and seedling process. The results of this study suggest the functional characteristics of soybeans through quantitative analysis of soyasapogenol. In addition, the concentration of soyasapogenol exhibited a change during the germination process, which was evaluated by the nutritional value of the soybean sprouts.

This study was carried out to investigate the variation of triterpene soyasapogenol A and B in soybean cultivars. Soyasapogenol A and B were isolated from acid hydrolysis of 80% aqueous ethanol extract of soybean and the structures of these soyasapogenols were characterized by 1H and 13C NMR analysis. And the distribution of soyasapogenol A and B were determined by high-performance liquid chromatography (HPLC) with variable wavelength detector (VWD). The soyasapogenol A and B contents of soybean cultivars ranged form 49.9 ㎍/g (Geomjeongsaeol) to 701.5㎍/g (Sorog) and from 91.4㎍/g (Danmi) to 2,315.9 ㎍/g (Daewonkong), respectively. Sorog cultivar showed the highest total soyasapogenol contents (2,773.8 ㎍/g), whereas Geomjeongkong 3 cultivar displayed the lowest (83.5㎍/g). The average content ratio of soyasapogenol B (1,061.4㎍/g) was significantly higher than that of soyasapogenol A (292.5 ㎍/g).