Soybean seeds contain many biologically active secondary metabolites, such as proteins, saponins, iso-flavones, phytic acids, trypsin inhibitors and phytosterols. Among them, saponins in soybeans have attracted consi-derable interest because of their health benefits. Soyasa-ponin 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 soyasa-pogenol 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 μg g-1 in soybean seeds and 1377.72 μg g-1 in soybean sprouts. Soybean sprouts were about 5% higher than soybean seeds in average total soyasapogenol concentra-tion. In the process of sprouting, the average soyasapogenol A content decreased by approximately 1.6%, but soyasa-pogenol 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 soyasa-pogenol concentration of soybean seeds were not signifi-cantly different (p<0.05) On average, small soybean seeds were increased by as much as 103.14 μg 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 μg g-1) was slightly higher than that of soybean with black (1260.30 μg g-1) or brown (1263.62 μg 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 character-istics of soybeans through quantitative analysis of soyasa-pogenol. In addition, the concentration of soyasapogenol exhibited a change during the germination process, which was evaluated by the nutritional value of the soybean sprouts.
MATERIALS AND METHODS
RESULTS AND DISCUSSION