Abstract: 【Objective】 The aim of this study was to explore the nutritional composition (isoflavonoids, amino acids, oligosaccharides and fatty acids) changes in soybean seeds induced by alginate oligosaccharide and provide a scientific basis for further utilization of soybean resource. 【Method】 Soybean seeds were induced by 4% (w/v) alginate oligosaccharides as elicitor. Isoflavones, amino acids, oligosaccharides and fatty acids were extracted from the induced and non-induced soybean seeds during different incubation times (1 d to 6 d). Contents of these compositions during different incubation times were detected and analyzed by HPLC, automatic amino acid analyzer or GC. 【Result】 Isoflavones, amino acids, oligosaccharides and fatty acids in induced soybeans changed dramatically. During the incubation period, glyceollins content was observed to have increased steadily from day 1 to day 5 having concentration of 0.01 mg·g^-1 DW at 1 d and 1.72 mg·g^-1 DW was recorded at 5 d. Highest accumulations were recorded for coumestrol (664.8 μg·g^-1 DW) and genistein (24.02 μg·g^-1 DW) at 5 d. While, daidzein decreased from 54.56 μg·g^-1 DW to 19.02 μg·g^-1 DW, respectively. Nutritional composition changes recorded during the five days were as follow: total amino acids content in induced soybeans seeds increased from 39.38% to 43.45% during the incubation period, contents of threonine and leucine were observed to have increased. Amino acids content recorded in the non-induced soybean seeds during analysis also showed nutritional changes, but the changes were generally lower than the changes observed in the induced soybean seeds. The content of sucrose in induced soybean seeds decreased from 53.72 mg·g^-1 DW to 21.5 mg·g^-1 DW, raffinose decreased totally at 3 d, while stachyose decreased at 4 d. In non-induced soybean seeds, sucrose decreased from 53.72 mg·g^-1 DW at 1 d to 23.09 mg·g^-1 DW, little amount of raffinose and stachyose were also detected. The total fatty acids content in the induced soybean seeds decreased from 14.27% to 14.01% during analysis, while the proportion of linoleic acid increased. 【Conclusion】 During the period of glyceollins accumulation in soybeans which were induced by oligosaccharides, the production of isoflavones in soybeans increased, the nutritional value of soybean protein was enhanced, flatulence factor in soybeans was eliminated, the property of soy oil was promoted. All of these changes were of great importance to the fully utilization of soybean resource.

Key words: alginate oligosaccharides, soybean, isoflavones, glyceollins, nutritional property.