Variation of Isoflavone Contents and Classification Using Multivariate Analysis in Korean Soybean Varieties Released from 1913 to 2013

This study was carried out to investigate the variation of 12 isoflavone components among 172 Korean soybean varieties released from 1913 to 2013. Cluster analysis was performed to classify the varieties based on the variation of isoflavone contents. Total isoflavone contents ranged from 206.3 μg/g to 2666.2 μg/g with an average of 837.2 μg/g. By each component, malonylgenistin content ranged from 99.2 μg/g to 1149.1 μg/g with the highest average of 390.0 μg/g, and glycitein content ranged from 0.1 μg/g to 2.4 μg/g with the lowest average of 0.8 μg/g. Among composition groups, the aglycone group contents ranged from 2.2 μg/g to 33.1 μg/g with the lowest average of 10.0 μg/g, and glucoside group contents ranged from 36.9 μg/g to 801.8 μg/g with an average of 202.4 μg/g. The malonylglucoside group contents ranged from 143.6 μg/g to 1796.4 μg/g with the highest average of 599.1 μg/g and acetylglucoside group contents ranged from 3.7 μg/g to 103.9 μg/g with an average of 27.5 μg/g. Varieties with high total isoflavone content were Aga8(2666.2 μg/g), Aga4(2569.3 μg/g), and Aga9(2345.0 μg/g) in bean sprouts group. The low total isoflavone content were observed from Deawang(328.8 μg/g) in soy sauce and paste group, Hanol(599.3 μg/g) in vegetable and early maturity group and Gemjeong1(664.1 μg/g) in cooking with rice group. The first three principal component axises accounted for 89.14% of the total variation observed. Dendrogram constructed using average linkage cluster method revealed that 172 Korean soybean varieties were divided into seven groups with the average distance of 0.8 between groups. The group Ⅰ includes 57.6% of the total varieties, which was the largest group among seven groups, followed by the group Ⅱ that includes 35.5% of the total varieties. However, the other groups were small groups containing less than five varieties. In comparison among the total isoflavone contents according to groups, the highest isoflavone content was observed in group Ⅵ with an average of 2526.9 μg/g, followed by group Ⅳ(1546.6 μg/g) and group Ⅴ(1503.5 μg/g). The others were found to contain low isoflavone content.