Krishna Hari Dhakal

Effects of light treatment on isoflavone content of germinated soybean seeds.

Our research objective was to increase isoflavone content in the germinated soybean seeds of four different varieties (Pungsannamulkong, Cheongjakong, Aga4, and Aga3) by optimizing light treatments (dark, greenhouse, fluorescent, incandescent, and ultraviolet lamps). The results demonstrated that the highest isoflavone content was produced from the Aga3 variety, which was developed by an interspecific cross between Eunhakong (Glycine max) and KLG10084 (G. soja) at the Plant Genetic Laboratory, Kyunpook National University. Aga3 is known to have one of the highest isoflavone content in the world at present. Our results recommend exposure of 7-day-old Aga3 sprouts to a combined light treatment of greenhouse lamps (12 h per day) and ultraviolet light (40 min per day) for maximum isoflavone production. Aga3 produced high levels of isoflavone because, in part, it contained very high isoflavone levels within the seed as compared with the other varieties. Under stress conditions, Aga3 could produce over 1.90 times more isoflavone than its seed content and 1.53 times more isoflavone than when grown under dark conditions.

Variation of unsaturated fatty acids in soybean sprout of high oleic acid accessions

Oleic acid and oleic acid rich foods may have beneficial health effects in humans. Soybeans with high oleic acid (around 80% in seed oil) have been developed. Soybean sprouts are an important vegetable in Korea, Japan and China. The objective of this study was to investigate the variation of unsaturated fatty acids, oleic, linoleic and α-linolenic acids, in sprouts from soybeans with normal and high oleic acid concentration. Twelve soybean accessions with six high oleic acid lines, three parents of high oleic acid lines, and three checks with normal and high oleic acid concentration were used in this study. The unsaturated fatty acid concentration in sprouts from each genotype was similar to the concentration in the ungerminated seed. The oleic acid concentration in the sprouts of high oleic acid lines (up to 80%) was still high (>70%) compared to the ungerminated seed. Thus, high oleic soybean varieties developed for sprout production could add valuable health benefits to sprouts and the individuals who consume this vegetable.

Fatty acid composition in each structural part of soybean seed and sprout

Fatty acid composition and C18:2:C18:3 of soybean seed and sprout is important for soy-industries to manufacture quality products. Six soybean varieties were analyzed by gas chromatography to determine fatty acid composition and linoleic to linolenic acid ratio (C18:2:C18:3) in seed, sprout, and their structural parts. In the case of whole seed and its structural parts, significant variation in fatty acid composition and C18:2:C18:3 were observed between varieties except palmitic acid (C16:0), while all the parameters were significantly different for seed parts. Significant interactions of variety with seed parts were observed for oleic acid (C18:1), C18:2 and C18:2:C18:3. The highest saturated fatty acid, C18:1 and polyunsaturated fatty acid were recorded in seed coat, cotyledon, and seed axis, respectively. The lowest C18:2:C18:3 was found in seed axis. In the case of sprout study, variety had significant effect on all the parameters observed for whole sprout, cotyledon, root, and except C18:3 for hypocotyl. Culture days had significant effect on C16:0, C18:2 and C18:3 in whole sprouts, while only on C18:3 and C18:2:C18:3 in cotyledon. For hypocotyl, culture days had significant effect on C18:1, C18:2 and C18:2:C18:3, however, C16:0, C18:1, C18:3, and C18:2:C18:3 were significantly different in root. In sprout, days and variety interacted significantly for C16:0, C18:3 and C18:2:C18:3, and C18:1, C18:2, C18:3, and C18:2:C18:3, respectively for whole, cotyledon, and root. The significantly lowest C18:2:C18:3 (1.1) was observed in hypocotyl and root of Hwangkeumkong in 5 days. Knowledge of fatty acid composition and C18:2:C18:3 of seed, sprout, and their parts could be applicable for oil and other soy-food industries to make quality products.